Fractals/Iterations in the complex plane/def cqp

Definitions

Order is not only alphabetical but also by topic so use find (Ctrl-f)


See also

AddressEdit

 "Internal addresses encode kneading sequences in human-readable form, when extended to angled internal addresses they distinguish hyperbolic components in a concise and meaningful way. The algorithms are mostly based on Dierk Schleicher's paper Internal Addresses Of The Mandelbrot Set And Galois Groups Of Polynomials (version of February 5, 2008) http://arxiv.org/abs/math/9411238v2." Claude Heiland-Allen[1]



types

  • finite / infinite
  • accesible/non-accesible
  • on the parameter plane / on th edynamic plane
  • simple/ angled
  • for Crossed Renormalizations[2]


InternalEdit

  • the internal address of a hyperbolic component A lists the periods of certain components that are “on the way” from the main cardioid to hyperbolic component A[3]
  • Internal addresses describe the combinatorial structure of the Mandelbrot set.[4] It is one of the Analytical Naming Systems[5][6]
  

Internal address:

  • is not constant within hyperbolic component. Example: internal address of -1 is 1->2 and internal address of 0.9999 is 1[7]
  • of hyperbolic component is defined as a internal address of it's center

angledEdit

Angled internal address is an extension of internal address. The angled internal address of the end of a finite chain of child bulbs   would be:

 

Examples:

  •   describes period 6 component which is a satelite of period 3 component.
  • Mandelbrot Artists by Claude Heiland-Allen

Elements

  • period of hyperbolic componnet
  • angle of internal ray

One can see the adress as:

  • sequence of hyperbolic components
  • path inside Mandelbrot set

Path inside Mandelbrot set:

  • start with center of period 1 ( nucleus)
  • internal ray with angle n/m
  • root point n/m ( bond)
  • internal angle
  • center with given period
  • ...

ProblemsEdit

Infinite sequences:

  • islands
  • infinite sequence of bifurcations

AngleEdit

Types of angleEdit

 
Principal branch or complex number argument
external angle internal angle plain angle
parameter plane      
dynamic plane    

where:

externalEdit

The external angle is a angle of

  • point of set's exterior
  • the boundary.

It is:

  • the same on all points on the external ray. It is important for proving connectedness of the Mandelbrot set.
  • a proper fraction
  • an approximation of directional derivative

internalEdit

The internal angle[8] is an angle of point of component's interior

  • it is a rational number and proper fraction measured in turns (see multiplier map)
  • it is the same for all point on the internal ray
  • in a contact point (root point) it agrees with the rotation number
  • root point has internal angle 0 (inside child component)
  • "The internal angles start at 0, at the cusp, and increase counterclockwise. " Robert Munafo[9]

 

See also

plainEdit

The plain angle is an angle of complex point = its argument[10]

UnitsEdit

  • turns
  • degrees
  • radians

Number typesEdit

Angle (for example, external angle in turns) can be used in different number types

Examples:

the external arguments of the rays landing at z = −0.15255 + 1.03294i are:[11]

 

where:

 

BifurcationEdit

  • Numerical Bifurcation Analysis of Maps

CoordinateEdit

Coordinate:


   "The coordinates are the current location, measured on the x-y-z axis. The gradient is a direction to move from our current location" Sadid Hasan[13]

CurvesEdit

Types:

  • topology:
    • closed versus open
    • simple versus not simple
  • other properities:
    • invariant
    • critical

Description[14]

  • plane curve = it lies in a plane.
  • closed = it starts and ends at the same place.
  • simple = it never crosses itself.

closedEdit

Closed curves are curves whose ends are joined. Closed curves do not have end points.

  • Simple Closed Curve: A connected curve that does not cross itself and ends at the same point where it begins. It divides the plane into exactly two regions (Jordan curve theorem). Examples of simple closed curves are ellipse, circle and polygons.[15]
  • Complex Closed Curve (not simple = non-simple) It divides the plane into more than two regions. Example: Lemniscates.

"non-self-intersecting continuous closed curve in plane" = "image of a continuous injective function from the circle to the plane"

CircleEdit

Inner circleEdit

Unit circleEdit

Unit circle   is a boundary of unit disk[16]

 

where coordinates of   point of unit circle in exponential form are:

 

Critical curvesEdit

Diagrams of critical polynomials are called critical curves.[17]

These curves create skeleton of bifurcation diagram.[18] (the dark lines[19])

dendritEdit

  • a locally connected branched curve
  • "Complex 1-variable polynomials with connected Julia sets and only repelling periodic points are called dendritic."[20]
  • "a dendrite is a locally connected continuum that does not contain Jordan curves." [21]
  • "a locally connected continuum without subsets homeomorphic to a circle"
  • connected with no interior


See also:

  • Misiurewicz point on the parameter plane
  • Dendrite Modeling: Modeling dendrites, including trees, lightning, river systems, and all manner of branching structures, has been frequently undertaken in computer graphics. We propose a new dendritic modeling framework using path planning as the basic operation[22]
  • Procedural Branching Texture[23]

Escape linesEdit

Escape line = boundary of escape time's level sets

"If the escape radius is equal to 2 the contour lines have a contact point (c= -2) and cannot be considered as equipotential lines" [24]

geodesicEdit

In geometry, a geodesic is a curve representing in some sense the shortest path (arc) between two points in a surface[25]

IntegralEdit

  • integral curve is a parameterized curve, whose tangent vectors agree with the vectors from this vector field. In physics, integral curves for an electric field or magnetic field are known as field lines.

InvariantEdit

Types:

  • topological
  • shift invariants

examples:


"Quasi-invariant curves are used in the study of hedgehog dynamics" RICARDO PEREZ-MARCO[30]

Examples:

  • field lines
    • external ray
    • internal ray

IsocurvesEdit

Isocurve = level curve = curve which consist of points which have the same value (level) of parameter / variable

Equipotential linesEdit

Equipotential lines = Isocurves of complex potential

"If the escape radius is greater than 2 the contour lines are equipotential lines" [31]

Examples

Jordan curveEdit

 
Illustration of the Jordan curve theorem. The Jordan curve (drawn in black) divides the plane into an "inside" region (light blue) and an "outside" region (pink).

Jordan curve = a simple closed curve that divides the plane into an "interior" region bounded by the curve and an "exterior" region containing all of the nearby and far away exterior points[32]

LaminationEdit

Lamination of the unit disk is a closed collection of chords in the unit disc, which can intersect only in an endpoint of each on the boundary circle[33][34]

It is a model of Mandelbrot or Julia set.

A lamination, L, is a union of leaves and the unit circle which satisfies:[35]

  • leaves do not cross (although they may share endpoints) and
  • L is a closed set.


"The pattern of rays landing together can be described by a lamination of the disk. As θ is varied, the diameter defined by θ/2 and (θ +1)/2 is moving and disconnecting or reconnecting chords. " Wolf Jung [36]

LeafEdit

Chords = leaves = arcs

A leaf on the unit disc is a path connecting two points on the unit circle.[37]


"In Thurston’s fundamental preprint, the two characteristic rays and their common landing point are the “minor leaf” of a “lamination”"[38]

Level curveEdit

LCM = Level Curve Method = method for drawing level curves


Examples:

  • equipotential line (the same potential)
  • external ray (the same external angle)
  • boundary of level set (see Level Set Method = LSM)

Open curveEdit

Curve which is not closed. Examples: line, ray.

PathEdit

  • Path in geometr is a curve


RayEdit

Rays are:

  • invariant curves
  • dynamic or parameter
  • external, internal or extended

ExtendedEdit

"We prolong an external ray R θ supporting a Fatou component U (ω) up to its center ω through an internal ray and call the resulting set the extended ray E θ with argument θ." Alfredo Poirier[39]

External rayEdit

The closure of an external ray is called a closed ray. If ray lands, then the closure of the ray is the union of the external ray and its landing point.[40]


  "A ray R is said to land or converge, if the accumulation set   is a singleton subset of J.  The conjecture that the Mandelbrot set is locally connected is equivalent to the continuous landing of all external rays."[41]

where:

  •   is a closure of   = the bar is taken to mean the closure rather than the complex conjugate
  • MLC = Mandelbrot Local connectivity Conjecture: M is locally connected[42]
  • singelton set is a set with exactly one element
 "If the MLC were proved true, the theorem of Caratheodory would give us an extension of the Riemann map   to  , giving a conformal equivalence of M with D. Given the fractal nature of M, this would be a very surprising result.[43]

Internal rayEdit

Definition:

  • "The internal rays are the preimages of the radial segments under the coordinate with componenet center corresponding to 0." Alfredo Poirier[44]
  • The internal rays of U are the images of radial lines under the Riemann maps.[45]

Internal rays are:

  • dynamic (on dynamic plane, inside filled Julia set)
  • |parameter (on parameter plane, inside Mandelbrot set) usuning multiplier map

dynamicEdit

For a parameter c with superattracting orbit: for every Fatou component   of filled julia set[46]   there is:

  • a unique periodic or pre-periodic point   of the super-attracting orbit
  • a Riemann map that maps:[47]

component to unit disc:

 


and point   to the origin:

 

The point   is called the center of component  .

For any angle   the pre-image of the radial segment of the unit disc

 

is called an internal ray of component   with well-defined landing point.

where:


See also:


intertwinedEdit

The internal rays are the curves that connects endpoints of external rays to the origin (the only pole) by winding in the specific way through the Julia set. Unlike the external rays the internal rays allways cross other internal rays, usually at multiple points, hence they are interwined[48]

parameterEdit


Escape routeEdit

Escape route is a path inside Mandelbrot set.


Escape route 1/2 <re>Plotting the Escape: An Animation of Parabolic Bifurcations in the Mandelbrot Set by Anne M. Burns. Mathematics Magazine Vol. 75, No. 2 (Apr., 2002), pp. 104-116 </ref>

  • is part of the real slice of the mandelbrot set)
  • part of the real line x=0

Steps:

  • start from center of period 1
  • go along internal ray 1/2 to root point of period 2 component
  • go along internal ray 0 to the center of period 2 component
  • go along internal ray 1/2 to root point of period 4 component
  • ...

SpiderEdit

A spider S is a collection of disjoint simple curves called legs [49] (extended rays = external + internal ray) in the complex plane connecting each of the post-critical points to infinity [50]

See:

SpineEdit

In the case of complex_quadratic_polynomial   the spine   of the filled Julia set   is defined as arc between  -fixed point and  ,

 

with such properties:

  • spine lies inside  .[51] This makes sense when   is connected and full [52]
  • spine is invariant under 180 degree rotation,
  • spine is a finite topological tree,
  • Critical point   always belongs to the spine.[53]
  •  -fixed point is a landing point of external ray of angle zero  ,
  •   is landing point of external ray  .

Algorithms for constructing the spine:

  • detailed version is described by A. Douady[54]
  • Simplified version of algorithm:
    • connect   and   within   by an arc,
    • when   has empty interior then arc is unique,
    • otherwise take the shortest way that contains  .[55]

Curve  :

 

divides dynamical plane into two components.


Computing external angle for c from centers of hyperbolic components and Misiurewicz points:

 The spine of K is the arc from beta to minus beta. Mark 0 each time C is above the spine and 1 each time it is below. You obtain the expansion in base 2 of the external argument theta of z by C. This simply comes from the two following facts:  
 *  0 < theta < 1/2 if acces to z is above the spine,   1/2 < theta < 1 if it is below
 * function f doubles the external arguments with respect to K, as well as the potential, since  Riemman map (Booettcher map) conjugates f to  .
 Note that if c and z are real, the tree reduces to the segment [beta',beta] of the real line, and the sequence of 0 and 1 obtained is just the kneading sequence studied by Milnor and Thurston (except for convention: they use 1 and -1). 
 This sequence appears now as the binary expansion of a number which has a geometrical interpretation. " A. Douady


Relation between spine and major leaf of the lamination

VeinEdit

"A vein in the Mandelbrot set is a continuous, injective arc inside in the Mandelbrot set"

"The principal vein   is the vein joining   to the main cardioid" (Entropy, dimension and combinatorial moduli for one-dimensional dynamical systems. A dissertation by Giulio Tiozzo)

DiscriminantEdit

In algebra, the discriminant of a polynomial is a polynomial function of its coefficients, which allows deducing some properties of the roots without computing them.

DistanceEdit

Distance Function

See also:

  • metric [56]
  • Algorithm
    • Distance Estimation Method
    • SDF = Signed Distance Function
  • distance fields
    • EDT Euclidean Distance Transform
    • SEDT = squared Euclidean distance transform. Algorithms generating distance fields from boolean fields:[57][58][59]
      • Marching Parabolas, a linear-time CPU-amenable algorithm.
      • Min Erosion, a simple-to-implement GPU-amenable algorithm.

DynamicsEdit

  • symbolic[60][61][62]
  • complex [63][64]
  • Arithmetic
  • combinatorial
  • local/global
  • discrete/continous
  • parabolic/hyperbolic/eliptic

Examples:

  • discrete local complex parabolic dynamics
evolution of dynamics along escape route 0 ( parabolic implosion); Im(c) = 0
parameter c location of c Julia set interior type of critical orbit dynamics critical point fixed points stability of alfa
c = 0 center, interior connected = Circle Julia set exist superattracting attracted to alfa fixed point fixed critical point equal to alfa fixed point, alfa is superattracting, beta is repelling r = 0
0<c<1/4 internal ray 0, interior connected exist attracting attracted to alfa fixed point alfa is attracting, beta is repelling 0 < r < 1.0
c = 1/4 cusp, boundary connected = cauliflower exist parabolic attracted to alfa fixed point alfa fixed point equal to beta fixed point, both are parabolic r = 1
c>1/4 external ray 0, exterior disconnected = imploded cauliflower disappears repelling repelling to infinity both finite fixed points are repelling r > 1


symbolicEdit

"Symbolic dynamics encodes:

entropyEdit

equationEdit

differentialEdit

differential equations

  • exact analytic solutions.
  • approximated solution
    • use perturbation theory to approximate the solutions

FieldEdit

Field is a region in space where each and every point is associated with a value.

The field types according to the value type:

  • scalar field
    • Distance field – Some mapping  , where for any given input the output is the distance to the nearest surface (where the field value is 0).[66]
  • vector field, for example gradient field

FunctionEdit

DerivativeEdit


angularEdit

Angular derivative [70]

The Schwarzian DerivativeEdit

The Schwarzian Derivative [71][72][73][74]

Wirtinger derivativesEdit

gradientEdit

the gradient is the generalization of the derivative for the multivariable functions[75][76]

definitions:

  • (field): Gradient field is the vector field with gradient vector
  • (function): The gradient of a scalar-valued multivariable function   is a vector-valued function denoted  
  • (vector): The gradient of the function f at the point (x,y) is defined as the unique vector (result of gradient function) representing the maximum rate of increase of a scalar function (length of the vector) and the direction of this maximal rate (angle of the vector). Such vector is given by the partial derivatives with respect to each of the independent variables[77]
  • (operator): Del or nabla is an gradient operator = a vector differential operator


Notations:

 

 



See also

  • Gradient Descent Algorithm[78][79]
  • Gradient Ascent Algorithm
  • image gradient

JacobianEdit

The Jacobian is the generalization of the gradient for vector-valued functions of several variables


multiplierEdit

The multiplier of a fixed point α is the derivative A′(α) calculated in any local chart around α[80]

GermEdit

Germ [81] of the function f in the neighborhood of point z is a set of the functions g which are indistinguishable in that neighborhood

 

See:

mapEdit

  • differences between map and the function [83]
  • Iterated function = map[84]
  • an evolution function[85] of the discrete nonlinear dynamical system[86]
 

is called map  , examples:

  • rational maps
  • exponential maps
  • trigonometric maps
  • landing map: " A theorem of Caratheodory states that if   is a full compact and locally connected set, then external rays land and the landing map   is continuous."[87]

types or namesEdit

BrjunoEdit

  • Brjuno function

Links:

harmonicEdit

An harmonic or spherical function is a:

  • "set of orthogonal functions all of whose curvatures are changing at the same rate."[88]
  • "harmonic functions relate two sets of different curves such that the rate of change of their respective curvatures is always equal. " and they are orthogonal
  • "One set of curves of the harmonic function expressed the pathways of minimal change in the potential for action, while the other, orthogonal curves expressed the pathways of maximum change in the potential for action."
  • "a pair of harmonic conjugate functions, u and v. They satisfy the Cauchy-Riemann equations. Geometrically, this implies that the contour lines of u and v intersect at right angles"[89]

Geometric examples:

  • " A set of concentric circles and radial lines comprises an harmonic function because both the circles and the radial lines intersect orthogonally and both have constant curvature."
  • "a set of orthogonal ellipses and hyperbolas."

How to find harmonic conjugate function ? [90]

meromorphicEdit

meromorphic maps: Those with NO FINITE, NON-ATTRACTING FIXED POINTS[91]

PolynomialEdit

CriticalEdit

Critical polynomial:

 

so

 

 

 

These polynomials are used for finding:

  • centers of period n Mandelbrot set components. Centers are roots of n-th critical polynomials   (points where critical curve Qn croses x axis)
  • Misiurewicz points  

post-critically finiteEdit

a post-critically finite polynomial = all critical points have finite orbit


ResurgentEdit

"resurgent functions display at each of their singular points a behaviour closely related to their behaviour at the origin. Loosely speaking, these functions resurrect, or surge up - in a slightly different guise, as it were - at their singularities"

J. Écalle, 1980[92][93][94]


transformationEdit

In mathematics, a transformation is a function f, usually with some geometrical underpinning, that maps a set X to itself, i.e. f : XX.[95][96][97]

Examples include:

  • linear transformations of vector spaces
  • geometric transformations
    • projective transformations
    • affine transformations
      • rotations
      • reflections
      • translations[98][99]


coordinate transformationsEdit

There are often many different possible coordinate systems for describing geometrical figures. The relationship between different systems is described by coordinate transformations, which give formulas for the coordinates in one system in terms of the coordinates in another system. For example, in the plane, if Cartesian coordinates (xy) and polar coordinates (rθ) have the same origin, and the polar axis is the positive x axis, then the coordinate transformation from polar to Cartesian coordinates is given by x = r cosθ and y = r sinθ.

With every bijection from the space to itself two coordinate transformations can be associated:

  • Such that the new coordinates of the image of each point are the same as the old coordinates of the original point (the formulas for the mapping are the inverse of those for the coordinate transformation)
  • Such that the old coordinates of the image of each point are the same as the new coordinates of the original point (the formulas for the mapping are the same as those for the coordinate transformation)

For example, in 1D, if the mapping is a translation of 3 to the right, the first moves the origin from 0 to 3, so that the coordinate of each point becomes 3 less, while the second moves the origin from 0 to −3, so that the coordinate of each point becomes 3 more.

Yoccoz’s functionEdit

glitchesEdit

 
Interior of the Cauliflower Julia set. .The black structure around fixed point and it's preimages is a numerical error (glitch) }}

Definition:

  • Incorrect (noisy) parts of renders[100] using perturbation technique
  • pixels which dynamics differ significantly from the dynamics of the reference pixel[101]"These can be detected and corrected by using a more appropriate reference."[102]


Examples:

grafEdit

Dessin d'enfantEdit

See also:

TreeEdit

Farey treeEdit

Farey tree = Farey sequence as a tree

Hubbard treeEdit

  • a simplified, combinatorial model of the Julia set (MARY WILKERSON)
  • "Hubbard trees are finite planar trees, equipped with self-maps, which classify postcritically finite polynomials as holomorphic dynamical systems on the complex plane." [103]
  • " Hubbard trees are invariant trees connecting the points of the critical orbits of post-critically finite polynomials. Douady and Hubbard showed in the Orsay Notes that they encode all combinatorial properties of the Julia sets. For quadratic polynomials, one can describe the dynamics as a subshift on two symbols, and itinerary of the critical value is called the kneading sequence." Henk Bruin and Dierk Schleicher[104]


Rooted treeEdit

rooted tree of preimages:

 

where a vertex   is connected by an edge with  .

IterationEdit

Iteration

MagnitudeEdit

  • magnitude of the point (complex number in 2D case) = it's distance from the origin[105]
  • radius is the absolute value of complex number (compare to arguments or angle)

MapEdit

description

typesEdit

  • The map f is hyperbolic if every critical orbit converges to a periodic orbit.[106]

Complex quadratic mapEdit

FormsEdit

c form:  Edit

quadratic map[107]

  • math notation:  
  • Maxima CAS function:
f(z,c):=z*z+c;
(%i1) z:zx+zy*%i;
(%o1) %i*zy+zx
(%i2) c:cx+cy*%i;
(%o2) %i*cy+cx
(%i3) f:z^2+c;
(%o3) (%i*zy+zx)^2+%i*cy+cx
(%i4) realpart(f);
(%o4) -zy^2+zx^2+cx
(%i5) imagpart(f);
(%o5) 2*zx*zy+cy

Iterated quadratic map

  • math notation
 
 

...

 

or with subscripts:

 
  • Maxima CAS function:
fn(p, z, c) :=
  if p=0 then z
  elseif p=1 then f(z,c)
  else f(fn(p-1, z, c),c);
zp:fn(p, z, c);
lambda form:  Edit

More description Maxima CAS code (here m not lambda is used):

(%i2) z:zx+zy*%i;
(%o2) %i*zy+zx
(%i3) m:mx+my*%i;
(%o3) %i*my+mx
(%i4) f:m*z+z^2;
(%o4) (%i*zy+zx)^2+(%i*my+mx)*(%i*zy+zx)
(%i5) realpart(f);
(%o5) -zy^2-my*zy+zx^2+mx*zx
(%i6) imagpart(f);
(%o6) 2*zx*zy+mx*zy+my*zx
Switching between formsEdit

Start from:

  • internal angle  
  • internal radius r

Multiplier of fixed point:

 

When one wants change from lambda to c:[108]

 

or from c to lambda:

 

Example values:

  r c fixed point alfa     fixed point  
1/1 1.0 0.25 0.5 1.0 0
1/2 1.0 -0.75 -0.5 -1.0 0
1/3 1.0 0.64951905283833*i-0.125 0.43301270189222*i-0.25 0.86602540378444*i-0.5 0
1/4 1.0 0.5*i+0.25 0.5*i i 0
1/5 1.0 0.32858194507446*i+0.35676274578121 0.47552825814758*i+0.15450849718747 0.95105651629515*i+0.30901699437495 0
1/6 1.0 0.21650635094611*i+0.375 0.43301270189222*i+0.25 0.86602540378444*i+0.5 0
1/7 1.0 0.14718376318856*i+0.36737513441845 0.39091574123401*i+0.31174490092937 0.78183148246803*i+0.62348980185873 0
1/8 1.0 0.10355339059327*i+0.35355339059327 0.35355339059327*i+0.35355339059327 0.70710678118655*i+0.70710678118655 0
1/9 1.0 0.075191866590218*i+0.33961017714276 0.32139380484327*i+0.38302222155949 0.64278760968654*i+0.76604444311898 0
1/10 1.0 0.056128497072448*i+0.32725424859374 0.29389262614624*i+0.40450849718747 0.58778525229247*i+0.80901699437495

One can easily compute parameter c as a point c inside main cardioid of Mandelbrot set:

 

of period 1 hyperbolic component (main cardioid) for given internal angle (rotation number) t using this c / cpp code by Wolf Jung[109]

 double InternalAngleInTurns;
 double InternalRadius;
 double t = InternalAngleInTurns *2*M_PI; // from turns to radians
 double R2 = InternalRadius * InternalRadius;
 double Cx, Cy; /* C = Cx+Cy*i */
 // main cardioid
 Cx = (cos(t)*InternalRadius)/2-(cos(2*t)*R2)/4; 
 Cy = (sin(t)*InternalRadius)/2-(sin(2*t)*R2)/4;

or this Maxima CAS code:

 
/* conformal map  from circle to cardioid (boundary
 of period 1 component of Mandelbrot set */
F(w):=w/2-w*w/4;

/* 
circle D={w:abs(w)=1 } where w=l(t,r) 
t is angle in turns ; 1 turn = 360 degree = 2*Pi radians 
r is a radius 
*/
ToCircle(t,r):=r*%e^(%i*t*2*%pi);

GiveC(angle,radius):=
(
 [w],
 /* point of  unit circle   w:l(internalAngle,internalRadius); */
 w:ToCircle(angle,radius),  /* point of circle */
 float(rectform(F(w)))    /* point on boundary of period 1 component of Mandelbrot set */
)$

compile(all)$

/* ---------- global constants & var ---------------------------*/
Numerator :1;
DenominatorMax :10;
InternalRadius:1;

/* --------- main -------------- */
for Denominator:1 thru DenominatorMax step 1 do
(
 InternalAngle: Numerator/Denominator,
 c: GiveC(InternalAngle,InternalRadius),
 display(Denominator),
 display(c),
  /* compute fixed point */
 alfa:float(rectform((1-sqrt(1-4*c))/2)), /* alfa fixed point */
 display(alfa)
 )$

Circle mapEdit

Circle map [110]

Doubling mapEdit

Angle doubling map

 

Feigenbaum mapEdit

"the Feigenbaum map F is a solution of Cvitanovic-Feigenbaum equation"[112]

First return mapEdit

"In contrast to a phase portrait, the return map is a discrete description of the underlying dynamics. .... A return map (plot) is generated by plotting one return value of the time series against the previous one "[114]

"If x is a periodic point of period p for f and U is a neighborhood of x, the composition   maps U to another neighborhood V of x. This locally defined map is the return map for x." (W P Thurston: On the geometry and dynamics of Iterated rational maps)

"The first return map S → S is the map defined by sending each x0 ∈ S to the point of S where the orbit of x0 under the system first returns to S." [115]

"way to obtain a discrete time system from a continuous time system, called the method of Poincar´e sections Poincar´e sections take us from: continuous time dynamical systems on (n + 1)-dimensional spaces to discrete time dynamical systems on n-dimensional spaces"[116]

postcritically finiteEdit

postcritically finite: maps whose critical orbits are all periodic or preperiodic[117]

  " In the theory of iterated rational maps, the easiest maps to understand are postcritically finite: maps whose critical orbits are all periodic or preperiodic. These maps are also the most important maps for understanding the combinatorial structure of parameter spaces of rational maps. "

A postcritically finite quadratic polynomial fc(z) = z^2+c may be:[118]

  • periodic of satellite type
  • periodic of primitive type
  • critically preperiodic (Misiurewicz type)

Examples are given by:

  • the Basilica Q(z) = z^2 − 1
  • the Kokopelli
  • P(z) = z^2 + i (dendrite)

Critically preperiodic polynomialsEdit

  • the critical point of fc is strictly preperiodic
  • parameter c is from Thurston-Misiurewicz points–values on the boundary of the Mandelbrot set = Misiurewicz point
  • Julia set is dendrite

Multiplier mapEdit

 
Mandelbrot set - multiplier map

Multiplier map   associated with hyperbolic component  

  • gives an explicit uniformization of hyperbolic component   by the unit disk  :
  • it is (d-1) to one function. Where d is a degree of iterated function

 

In other words it maps hyperbolic component H to unit disk D.

It maps point c from parameter plane to point b from reference plane:

 

where:

  • c is a point in the parameter plane
  • b is a point in the reference plane. It is also internal coordinate
  •   is a multiplier map

Multiplier map is a conformal isomorphism.[119]

It can be computed using:

Approximation

Riemann mapEdit

Riemann mapping theorem[120] says that every simply connected subset U of the complex number plane can be mapped to the open unit disk D

 

where:

  • D is a unit disk  
  • f is Riemann map (function). It is 1to-1 function
  • U is subset of complex plane

Examples (approximations of Riemann mapping):

  • multiplier map on the parameter plane
  • binary decomposition
  • Böttcher coordinates
    • on the parameter plane the Riemann map for the complement of the Mandelbrot set
    • on dynamic plane[121]
      • for the Fatou component containing a superattracting fixed point for a rational map[122]
      • a Riemann map for the complement of the filled Julia set of a quadratic polynomial with connected Julia: "The Riemann map for the central component for the Basilica was drawn in essentially the same way, except that instead of starting with points on a big circle, I started with sample points on a circle of small radius (e.g. 0.00001) around the origin." Jim Belk

function:

  • explicit formula (only in simple cases)
  • numerical approximation (in most of the cases)[123]
    • Zipper
    • " Thurston and others have done some beautiful work involving approximating arbitrary Riemann maps using circle packings. See Circle Packing: A Mathematical Tale by Stephenson."
    • " To some extent, constructing a Riemann map is simply a matter of constructing a harmonic function on a given domain (as well as the associated harmonic conjugate), subject to certain boundary conditions. The solution to such problems is a huge topic of research in the study of PDE's, although the connection with Riemann maps is rarely mentioned." Jim Belk[124]

PDE's approach to construct a Riemann map explicitly on a given domain D

  • First, translate the domain so that it contains the origin.
  • Next, use a numerical method to construct a harmonic function F satisfying
  

for all  , and let

  

Then

  •  
  •  
  • and   is harmonic

so:

  • R is the radial component (i.e. modulus) of a Riemann map on D.
  • The angular component can now be determined by the fact that its level curves are perpendicular to the level curves of R, and have equal angular spacing near the origin."


"Using the Riemann mapping BM we can define the parameter external rays and equipotentials as the preimages of the straight rays going to ∞ and round circles centered at 0. This gives us two orthogonal foliations in the complement of the Mandelbrot set." [125]


See

Rotation mapEdit

     "If a is rational, then every point is periodic. If a is irrational, then every point has a dense orbit." David Richeson[129]


rationalEdit

Rotation map   describes counterclockwise rotation of point   thru   turns on the unit circle:

  

It is used for computing:

irrationalEdit

Shift mapEdit

names:

  • bit shift map (because it shifts the bit) = if the value of an iterate is written in binary notation, the next iterate is obtained by shifting the binary point one bit to the right, and if the bit to the left of the new binary point is a "one", replacing it with a zero.
  • 2x mod 1 map (because it is math description of its action)

Shift map (one-sided binary left shift) acts on one-sided infinite sequence of binary numbers by

  

It just drops first digit of the sequence.

   
   

If we treat sequence as a binary fraction:

  

then shift map = the dyadic transformation = dyadic map = bit shift map= 2x  mod 1 map = Bernoulli map = doubling map = sawtooth map

  

and "shifting N places left is the same as multiplying by 2 to the power N (written as 2N)"[130] (operator <<)

In Haskell:

 shift k = genericTake q . genericDrop k . cycle  -- shift map

See also:

NumberEdit

complex numberEdit

  • numerical value: x+y*i
  • vector from origin to point (x,y)
  • point (x,y) od 2D Cartesion plain

constantEdit

Fegenbaum constantEdit

  • first (delta)[131]
  • second (alpha)


How to compute:

degreeEdit

It hase many meanings:[132]

  • unit of the angle
  • degree of a function
    • polynomial
    • rational function[133]

MultiplierEdit

The multiplier of periodic z-point:[134][135]

  • is a complex number
  • "The value of   is the same at any point in the orbit of a: it is called the multiplier of the cycle."[136]
  • The multiplier is invariant under conjugacy[137]
  • Linearizability depends on the multiplier


Math notation:

 

Maxima CAS function for computing multiplier of periodic cycle:

m(p):=diff(fn(p,z,c),z,1);

where p is a period. It takes period as an input, not z point.

period    
1    
2    
3    



It is used to:

  • compute stability index of periodic orbit (periodic point) =   (where r is a n internal radius)
  • multiplier map


"The multiplier of a fixed point gives information about its stability (the behaviour of nearby orbits)" [138]



See also:

Rotation numberEdit

The rotation number[139][140][141][142][143] of the disk (component) attached to the main cardioid of the Mandelbrot set is a proper, positive rational number p/q in lowest terms where:

  • q is a period of attached disk (child period) = the period of the attractive cycles of the Julia sets in the attached disk
  • p describes fc action on the cycle: fc turns clockwise around z0 jumping, in each iteration, p points of the cycle [144]

Features:

  • in a contact point (root point) it agrees with the internal angle
  • the rotation numbers are ordered clockwise along the boundary of the componant
  • " For parameters c in the p/q-limb, the filled Julia set Kc has q components at the fixed point αc . These are permuted cyclically by the quadratic polynomial fc(z), going p steps counterclockwise " Wolf Jung

Winding numberEdit

  • of the map (iterated function)[145][146]
    • "the winding number of the dynamic ray at angle a around the critical value, which is defined as follows: denoting the point on the dynamic a-ray at potential t greater or equal to zero by zt and decreasing t from +infinity to 0, the winding number is the total change of arg(zt - c) (divided by 2*Pi so as to count in full turns). Provided that the critical value is not on the dynamic ray or at its landing point, the winding number is well-defined and finite and depends continuously on the parameter. " DIERK SCHLEICHER [147]
    • "the winding number of the dynamic ray at angle ϑ around the critical value, which is defined as follows: denoting the point on the dynamic ϑ-ray at potential t ≥ 0 by zt and decreasing t from +∞ to 0, the winding number is the total change of arg(zt − c) (divided by 2π so as to count in full turns). Provided that the critical value is not on the dynamic ray or at its landing point, the winding number is well-defined and finite and depends continuously on the parameter. When the parameter c moves in a small circle around c0 and if the winding number is defined all the time, then it must change by an integer corresponding to the multiplicity of c as a root of z(c) − c. However, when the parameter returns back to where it started, the winding number must be restored to what it was before. This requires a discontinuity of the winding number, so there are parameters arbitrarily close to c0 for which the critical value is on the dynamic ray at angle ϑ, and c0 is a limit point of the parameter ray at angle ϑ. Since this parameter ray lands, it lands at c0."
  • of the curve [148][149]
    • the winding number of a curve is the number of complete rotations, in the counterclockwise sense, of the curve around the point(0, 0).[150]
    • w(γ, x) = number of times curve γ winds round point x. The winding number is signed: + for counterclockwise, − for clockwise.[151]


Computing winding number of the curve (which is not crossing the origin) using:

  • numerical integration
  • computational geometry

The discrete winding number = winding number of polygon approximating curve

OrbitEdit

Orbit is a sequence of points[152]

  • phase space trajectories of dynamical systems
  • The orbit of periodic point is finite and it is called a cycle.

BackwardEdit

CriticalEdit

Critical orbit is forward orbit of a critical point.

ForwardEdit

Homoclinic / heteroclinicEdit


InverseEdit

Inverse = Backward


periodicEdit

skippedEdit

  • set containing first n iterations of initial point without initial point and its k iterations
  • number of elements = n - k

 

It is used in the average colorings

truncatedEdit

  • set containing initial point and first n iterations of initial point
  • number of elements = n+1

 

ParameterEdit

Parameter

PeriodEdit

Period of point   under the iterarted function f is the smallest positive integer value p for which this equality

 

holds is the period[154] of the orbit.[155]

  is a point of periodic orbit (limit cycle)  .

More is here

PlaneEdit

Planes [156]

Douady’s principle: “sow in dynamical plane and reap in parameter space”.


2-sphereEdit

In topology: two-dimensional sphere = 2-sphere = the two-dimensional surface of a three-dimensional ball[157]

Geometrically, the set of extended complex numbers is referred to as the Riemann sphere or extended complex plane.

partitionEdit

Examples:

  • Markow
  • Yoccoz puzzle


Kneading partition of the dynamic planeEdit

In case of critically preperiodic polynomials the partition of the dynamic plane used in the definition of the kneading sequence.

Partition is formed by the dynamic rays at angles:

  • t/2
  • (t + 1)/2

which land together at the critical point.

Angle t is angle which lands on the critical value:

 

Spine partition of the dynamic planeEdit

Curve  :

 

where:

divides dynamical plane into two components.

crossing/noncrossingEdit

noncrossing: "A partition of a (finite) set is just a subdivision of the set into disjoint subsets. If the set is represented as points on a line (or around the edge of a disc), we can represent the partition with lines connecting the dots. The lines usually have lots of crossings. When the partition diagram has no crossing lines, it is called a non-crossing partition. ... They have a lot of beautiful algebraic structure, and are related to lots of old enumeration problems. More recently (and importantly), they turn out to be a crucial tool in understanding how the eigenvalues of large random matrices behave." Todd Kemp (UCSD)[158]


Key words:

  • Enumerative combinatorics

typesEdit

  • slit plane = plane with the slit deleted[159]: Let S be the "slit plane"  
  • chessboard or checkerboards

types in case of discrete dynamical systemEdit

Dynamic plane or phase spaceEdit

  • z-plane for fc(z)= z^2 + c
  • z-plane for fm(z)= z^2 + m*z

Parameter planeEdit

See:[160]

Types of the parameter plane:

  • c-plane (standard plane)
  • exponential plane (map) [161][162]
  • flatten' the cardiod (unroll) [163][164] = "A region along the cardioid is continuously blown up and stretched out, so that the respective segment of the cardioid becomes a line segment. .." (Figure 4.22 on pages 204-205 of The Science Of Fractal Images)[165]
  • transformations [166]

PointsEdit

Band-mergingEdit

the band-merging points are Misiurewicz points[167]

BiaccessibleEdit

If there exist two distinct external rays landing at point we say that it is a biaccessible point.[168]

blowup pointEdit

blowup point = parameter for which the critical orbits map to ∞, so the Julia set is the entire sphere [169]

BuriedEdit

" a point of the Julia set is buried if it is not in the boundary of any Fatou component." [170]

polynomials do not have buried points

some rational Julia sets have (Residual Julia Set = Buried Points)

CenterEdit

Nucleus or center of hyperbolic componentEdit

A center of a hyperbolic component H is a parameter   (or point of parameter plane) such that

  • the corresponding periodic orbit has multiplier= 0." [171]
  • it has a superstable periodic orbit


Synonyms:

  • Nucleus of a Mu-Atom [172]

How to find center/s ?

Center of Siegel DiscEdit

Center of Siegel disc is a irrationally indifferent periodic point.

Mane's theorem:

"... appart from its center, a Siegel disk cannot contain any periodic point, critical point, nor any iterated preimage of a critical or periodic point. On the other hand it can contain an iterated image of a critical point." [173]

CriticalEdit

A critical point[174] of   is a point   in the dynamical plane such that the derivative vanishes:

 

A critical value is an image of critical point

complex quadratic polynomialEdit

For the complex quadratic polynomial in the c form

 

implies

 

we see that the only (finite) critical point of   is the point  .

  is an initial point for Mandelbrot set iteration.[175]

CutEdit

 
The "neck" of this eight-like figure is a cut-point.
 
Cut points in the San Marco Basilica Julia set. Biaccessible points = landing points for 2 external rays

Cut point k of set S is a point for which set S-k is dissconected (consist of 2 or more sets).[176] This name is used in a topology.

Examples:

  • root points of Mandelbrot set
  • Misiurewicz points of boundary of Mandelbrot set
  • cut points of Julia sets (in case of Siegel disc critical point is a cut point)

These points are landing points of 2 or more external rays.

Point which is a landing point of 2 external rays is called biaccesible

Cut ray is a ray which converges to landing point of another ray.[177] Cut rays can be used to construct puzzles.

Cut angle is an angle of cut ray.

fixedEdit

Periodic point when period = 1

FeigenbaumEdit

The Feigenbaum Point[178] is a:

  • point c of parameter plane
  • is the limit of the period doubling cascade of bifurcations
  • the accumulation point of the period-doubling cascade in the real-valued x^2+c mapping
  • an infinitely renormalizable parameter of bounded type
  • boundary point between chaotic (-2 < c < MF) and periodic region (MF< c < 1/4)[179]

 

Generalized Feigenbaum points are:

  • the limit of the period-q cascade of bifurcations
  • landing points of parameter ray or rays with irrational angles

Examples:

  •  
  • -.1528+1.0397i)

The Mandelbrot set is conjectured to be self- similar around generalized Feigenbaum points[180] when the magnification increases by 4.6692 (the Feigenbaum Constant) and period is doubled each time[181]

n Period = 2^n Bifurcation parameter = cn Ratio  
1 2 -0.75 N/A
2 4 -1.25 N/A
3 8 -1.3680989 4.2337
4 16 -1.3940462 4.5515
5 32 -1.3996312 4.6458
6 64 -1.4008287 4.6639
7 128 -1.4010853 4.6682
8 256 -1.4011402 4.6689
9 512 -1.401151982029
10 1024 -1.401154502237
infinity -1.4011551890 ...

Bifurcation parameter is a root point of period = 2^n component. This series converges to the Feigenbaum point c = −1.401155

The ratio in the last column converges to the first Feigenbaum constant.

" a "Feigenbaum point" (an infinitely renormalizable parameter of bounded type, such as the famous Feigenbaum value which is the limit of the period-2 cascade of bifurcations), then Milnor's hairiness conjecture, proved by Lyubich, states that rescalings of the Mandelbrot set converge to the entire complex plane. So there is certainly a lot of thickness near such a point, although again this may not be what you are looking for. It may also prove computationally intensive to produce accurate pictures near such points, because the usual algorithms will end up doing the maximum number of iterations for almost all points in the picture." Lasse Rempe-Gillen[182]

FibonacciEdit

Fibonacci point[183] [184][185]

infinityEdit

The point at infinity [186]" is a superattracting fixed point, but more importantly its immediate basin of attraction - that is, the component of the basin containing the fixed point itself - is completely invariant (invariant under forward and backwards iteration). This is the case for all polynomials (of degree at least two), and is one of the reasons that studying polynomials is easier than studying general rational maps (where e.g. the Julia set - where the dynamics is chaotic - may in fact be the whole Riemann sphere). The basin of infinity supports foliations into "external rays" and "equipotentials", and this allows one to study the Julia set. This idea was introduced by Douady and Hubbard, and is the basis of the famous "Yoccoz puzzle"." Lasse Rempe-Gillen[187]

 
Mandelbrot set at Fibonacci point

MisiurewiczEdit

Misiurewicz point[188] = " parameters where the critical orbit is pre-periodic.

Myrberg-FeigenbaumEdit

MF = the Myrberg-Feigenbaum point is the different name for the Feigenbaum Point.

Parabolic pointEdit

parabolic points: this occurs when two singular points coalesce in a double singular point (parabolic point)[189]


"the characteristic parabolic point (i.e. the parabolic periodic point on the boundary of the critical value Fatou component) of fc"[190]

PeriodicEdit

Point z has period p under f if:

 

In other words point is periodic

See also:

PinchingEdit

"Pinching points are found as the common landing points of external rays, with exactly one ray landing between two consecutive branches. They are used to cut M or K into well-defined components, and to build topological models for these sets in a combinatorial way. " (definition from Wolf Jung program Mandel)


other names

  • pinch points
  • cut points

See for examples:

  • period 2 = Mandel, demo 2 page 3.
  • period 3 = Mandel, demo 2 page 5 [191]

PoolEdit

"A point in the dendrite is called a pool if it is the landing point for two external rays, both of whose angles are of the form

 

for some k, n ∈ N, where k ≡ 1 mod 6.

...

central pool ... it is geometrically the center of the dendrite; a one half rotation around this point maps the dendrite to itself." [192]

post-criticalEdit

A post-critical point is a point

 

where   is a critical point.[193]


See also:

precriticalEdit

precritical points, i.e., the preimages of the critical point

reference pointEdit

Reference point of the image:

  • its orbit (reference orbit) is computed with arbitrary precision and saved
  • orbits of the other points of the image (no-reference points) are computed from reference orbit using standard precision (with hardware floating point numbers) = faster then using arbitrary precision

renormalizableEdit

point of the parameter plane " is renormalizable if restriction of some of its iterate gives a polinomial-like map of the same or lower degree. " [194]

infinitely renormalizableEdit

" a "Feigenbaum point" (an infinitely renormalizable parameter of bounded type, such as the famous Feigenbaum value which is the limit of the period-2 cascade of bifurcations), then Milnor's hairiness conjecture, proved by Lyubich, states that rescalings of the Mandelbrot set converge to the entire complex plane. So there is certainly a lot of thickness near such a point, although again this may not be what you are looking for. It may also prove computationally intensive to produce accurate pictures near such points, because the usual algorithms will end up doing the maximum number of iterations for almost all points in the picture." Lasse Rempe-Gillen[195]

IMMEDIATE RENORMALIZATIONEdit

" A cubic polynomial P with a non-repelling fixed point b is said to be immediately renormalizable if there exists a (connected) quadratic-like invariant filled Julia set K∗ such that b ∈ K∗ . In that case exactly one critical point of P does not belong to K∗." [196]

repellingEdit

Virtually repellingEdit

virtually repelling fixed points[197]

root or bondEdit

The root point of the hyperbolic component of the Mandelbrot set:

  • A point where two mu-atoms meet
  • has a rotational number 0
  • it is a biaccesible point (landing point of 2 external rays)

Names:

singularEdit

the singular points of a dynamical system

In complex analysis there are four classes of singularities:

  • Isolated singularities: Suppose the function f is not defined at a, although it does have values defined on U \ {a}.
    • The point a is a removable singularity of f if there exists a holomorphic function g defined on all of U such that f(z) = g(z) for all z in U \ {a}. The function g is a continuous replacement for the function f.
    • The point a is a pole or non-essential singularity of f if there exists a holomorphic function g defined on U with g(a) nonzero, and a natural number n such that f(z) = g(z) / (za)n for all z in U \ {a}. The least such number n is called the order of the pole. The derivative at a non-essential singularity itself has a non-essential singularity, with n increased by 1 (except if n is 0 so that the singularity is removable).
    • The point a is an essential singularity of f if it is neither a removable singularity nor a pole. The point a is an essential singularity if and only if the Laurent series has infinitely many powers of negative degree.
  • Branch points are generally the result of a multi-valued function, such as   or   being defined within a certain limited domain so that the function can be made single-valued within the domain. The cut is a line or curve excluded from the domain to introduce a technical separation between discontinuous values of the function. When the cut is genuinely required, the function will have distinctly different values on each side of the branch cut. The shape of the branch cut is a matter of choice, however, it must connect two different branch points (like   and   for  ) which are fixed in place.

tipEdit

  • from Mu-Ency: "the point in a primary filament that has the simplest external angle; this is the point that you get by appending FS[(1/2B1)] an infinite number of times to the primary filament's name." This is also the "limit" of the ... series.
  • Misurewicz point

tripleEdit

"A point in the dendrite is called a triple point if its removal separates the dendrite into three connected components. Such a point is the landing point for three external rays, whose angles all have of the form

 

for some k, n ∈ N, where k is congruent to 1, 2 or 4, mod 7." Will Smith in Thompson-Like Groups for Dendrite Julia Sets

PortraitEdit

orbit portraitEdit

typesEdit

There are two types of orbit portraits: primitive and satellite.[199] If   is the valence of an orbit portrait   and   is the recurrent ray period, then these two types may be characterized as follows:

  • Primitive orbit portraits have   and  . Every ray in the portrait is mapped to itself by  . Each   is a pair of angles, each in a distinct orbit of the doubling map. In this case,   is the base point of a baby Mandelbrot set in parameter space.
  • Satellite (non-primitive) orbit portraits have  . In this case, all of the angles make up a single orbit under the doubling map. Additionally,   is the base point of a parabolic bifurcation in parameter space.

CriticalEdit

Critical orbit portrait = portrait of the critical orbit

... for the polynomial   we may note the critical orbit portrait:


 


for this map, or we may double the angles of external rays and record the locations of landing points in order to observe the same behavior." [200]

PrecisionEdit

Precision of:

  • data type used for computation. Measured in bits (width of significant (fraction) = number of binary digits) or in decimal digits
  • input values
  • result (number of significant figures)

See:

  • Numerical Precision: " Precision is the number of digits in a number. Scale is the number of digits to the right of the decimal point in a number. For example, the number 123.45 has a precision of 5 and a scale of 2."[201]
  • error [202]

PrincipleEdit

Douady’s principleEdit

Douady’s principle: “sow in dynamical plane and reap in parameter space”.

ProblemEdit

small divisor problemEdit

Types

  • One-Dimensional Small Divisor Problems[203] (On Holomorphic Germs and Circle Diffeomorphisms)
  • linearization problem in complex dimension one dynamical systems: "Given a fixed point of a differentiable map, seen as a discrete dynamical system, the linearization problem is the question whether or not the map is locally conjugated to its linear approximation at the fixed point. Since the dynamics of linear maps on finite dimensional real and complex vector spaces is completely understood, the dynamics of a map on a finite dimensional phase space near a linearizable fixed point is tractable."[204]

Where it can be found:

  • stability in mechanics, particularly in celestial mechanics
  • relations between the growth of the entries in the continued fraction expansion of t and the behaviour of f around z=0 under iteration.

See:

Processes or transformations and phenomenonaEdit

Aliasing and antialiasingEdit

ConjugationEdit

Topological conjugacyEdit

two functions are said to be topologically conjugate if there exists a homeomorphism that will conjugate the one into the other. Topological conjugacy also known as topological equivalence[206] is important in the study of iterated functions and more generally dynamical systems, since, if the dynamics of one iterative function can be determined, then that for a topologically conjugate function follows trivially.

To illustrate this directly: suppose that   and   are iterated functions, and there exists a homeomorphism   such that

 

so that   and   are topologically conjugate. Then one must have

 

and so the iterated systems are topologically conjugate as well. Here,   denotes function composition.

 

Commutative square diagram

  • a collection of maps
  • square diagram that commutes = all map compositions starting from the same set A and ending with the same set D give the same result


Examples

  • The logistic map and the tent map are topologically conjugate.[207]
  • The logistic map of unit height and the Bernoulli map are topologically conjugate.[citation needed]
  • For certain values in the parameter space, the Hénon map when restricted to its Julia set is topologically conjugate or semi-conjugate to the shift map on the space of two-sided sequences in two symbols.[208]

Contraction and dilatationEdit

  • the contraction z → z/2
  • the dilatation z → 2z.

convolutionEdit

In the digital image processing[209]: image convolution Convolution is used to

  • extract certain features from an input image, like edge


Image convolutions by dimensions of the kernel array:

  • 1D
    • LIC
  • 2D
    • Gaussian blur (Gaussian smoothing)
    • Sobel filter


See also

  • feature detection (Feature extraction)
    • edge detection
    • Ridge detection
    • Motion detection
    • Blob detection

differentiationEdit

Method of computing the derivative of a mathematical function

types:

  • symbolic differentiation
  • Automatic Differentiation (AD)[210]
  • numeric differentiation [211][212][213] = the method of finite differences[214]

DiscretizationsEdit

  • discretization[215] and its reverse [216]
  • discretize/homogenize in the DDG (Discrete Differential Geometry)


Discretization is the process of transferring continuous functions, models, variables, and equations into discrete counterparts.[217]

Examples:

  • Cartesian coordinate system ( regular grid ) of continous space

distorsionEdit

Implosion and explosionEdit

 
Explosion (above) and implosion (below)

Implosion is:

  • the process of sudden change of quality fuatures of the object, like collapsing (or being squeezed in)
  • the opposite of explosion

Example:

  • parabolic implosion in complex dynamics ( )
    • when filled Julia for complex quadratic polynomial set looses all its interior (when c goes from 0 along internal ray 0 thru parabolic point c=1/4 and along extrnal ray 0 = when c goes from interior, crosses the boundary to the exterior of Mandelbrot set)[219]
    • " We can see that   looks somewhat like   from the "outside", but on the "inside" there are curlicues; pairs of them are vaguely reminiscent of "butterflies". As t→0, these butterflies persist and remain uniformly large. We think of t as representing time, which decreases to 0. The fact that they suddenly disappear for t=0 is the phenomenon called "implosion". Or, if we think of time starting at t=0, then the instantaneous appearance of large "butterflies" for t>0 may be thought of as "explosion". "
    • the Julia set implodes when under small perturbations (epsilon) near parabolic parameter (like c = 1/4)[220]
  • Semi-parabolic implosion in  [221]


Explosion is a:

  • sudden change of quality fuatures of the object in an extreme manner,
  • the opposite of implosion

Example: in exponential dynamics when λ> 1/e, the Julia set of   is the entire plane.[222]

integratingEdit

  • integrating along some vector field means finding a solution curve. Example: finding extrrernal ray using Runge-Kutta method for numerical integration[223]


LinearizationEdit

  • changing from non-linear to linear
  • " ... turn the perturbated linear map   into the exactly linear map   (it linearizes  )" Jean-Christophe Yoccoz[224]
  • linearization in english wikipedia
  • Linearization in scholarpedia
  • "System is linearizable at the origin if and only if there exists a change of coordinates which linearizes the system, that is, all the coefficients of the normal form vanish." [225]
 
Linearization with inverse function


Examples:

  • Parabolic Linearization

MatingEdit

Mating [226]

NormalizationEdit

Normalize

  • normalize = transformation to the model[227]
  • " normalize this vector so it has modulus one " A Cheritat
  • move fixed point to the origin (z = 0)
  • mapping the range of variable to standard range
    • [0.0, 1.0]
    • [0,255], like rgb values
  • converting closed curve to unit circle
  • converting closed curves to concentric circles with center at the origin[228]

See also:

  • uniformization
  • renormalization

ParametrizationEdit

  • Parametrization is the process of finding parametric equations of a curve[229]

PerturbationEdit

  • Perturbation technque for fast rendering the deep zoom images of the Mandelbrot set[230]
  • perturbation of parabolic point [231]
  • use perturbation theory to approximate the solutions of the differential equations
  • perturbation of point x:   where epsilon is absolute value of approximation error[232]
  • adding some small value ( epsilon denoted by Greek letter  ) to the constant value to see how function changes near hard to analyze values

SeparationEdit

  • "the double fixed point 0 of   usually splits into two fixed points. ... These points separate at some speed" ( PARABOLIC IMPLOSION. A MINI-COURSE by ARNAUD CHERITAT )


RenormalizationEdit

"to any quadratic map f we can associate a canonical sequence of periods p1 < p2 <... for which f is renormalizable.

Depending on whether the sequence is:

  • empty
  • finite
  • infinite

the map f is called respectively:

  • non-renormalizable
  • at most finitely renormalizable
  • infinitely renormalizable" [233]


"Sectorial renormalizations are useful in the nonlinearizable situation. " Ricardo Pérez-Marco[234]


The self-similarity is a result of something called "renormalization" (which as far as I know is not related to the concept with the same name in quantum field theory). Jim Belk[235]


Examples:

SurgeryEdit

  • surgery in differential topology [237]
  • regluing [238]

Links:

TuningEdit

UniformizationEdit

Uniformization of 
  • Hyperbolic Components of Mandelbrot set to the unit disc = multiplier map
  • basin of superattractive fixed point - Bottcher map (The Bottcher uniformization theorem)

VectorisationEdit

property or featureEdit

behaviorEdit

  • local behavior is the behavior of a complex analytic function near some point (fixed, periodic) = Local theory of periodic orbits = local dynamics
  • global behavior


DensityEdit

density of the imageEdit

Dense image[240][241][242]

  • downsaling with gamma correction[243]
  • path finding[244]
  • supersampling: "ots of detail but fractal fades away as you get more accurate, as n increases in nxn supersampling" TGlad


Hyperbolic/parabolic/elipticEdit

The meaning of the terms "elliptic, hyperbolic, parabolic" in different disciplines in mathematics[245]

InvariantEdit

sth is invariant with respect to the transformation = non modified, steady

Topological methods for the analysis of dynamical systems

Invariants type

  • metric invariants
  • dynamical invariants,
  • topological invariants.

dynamicalEdit

Dynamical invariants = invariants of the dynamical system

Dynamical Invariants Derived from Recurrence Plots[246]

OrientationEdit

  • A compass rose: Notice that the convention for measuring angles is different to the convention we used in the unit circle definition of the trigonometric functions.
    • Firstly 0o is North, rather than the x axis.
    • Secondly the direction in which angles increase is clockwise rather than counter-clockwise.
  • Unit circle :
    • the direction in which angles increase is counter-clockwise
    • angle zero is the x axis direction
  • Cartesian coordinate system[247]

smoothEdit

smooth = changing without visible (noticeable) edges

use:

  • smooth gradient

similar:

  • continuous

compare:

  • discrete

StabilityEdit

  • stability of quasiperiodic motion under small perturbation. In the celestial mechanics dynamics of 3 bodies around sun is described by the system of differential equations. In such case it "becomes fantastically complicated and remains largely mysterious even today." See KAM = Kolmogorov–Arnold–Moser theorem and small divisor problem
  • stability of the fixed point under small perturbation
  • there is equivalence (for |f′(0)| ≤ 1) of stability (a topological notion) and linearizability (an analytical notion)


Compare with:

RadiusEdit

Radius of complex numberEdit

The absolute value or modulus or magnitude or radius of a complex number

Conformal radiusEdit

Conformal radius of Siegel Disk [248][249]

Escape radius (ER)Edit

Escape radius (ER) or bailout value is a radius of circle centered at origin (z=0). This set is used as a target set in the bailout test (escape time method = ETM)

MinimalEdit

Minimal Escape Radius should be grater or equal to 2:

 

Better estimation is:[250][251]

 

crossingEdit

How to choose parameters for which level curves cross critical point (and its preimages)? Choose escape radius equal to n=th iteration of critical value.



// find such ER for LSM/J that level curves croses critical point and it's preimages
double GiveER(int i_Max){

	complex double z= 0.0; // critical point
	int i;
	 ; // critical point escapes very fast here. Higher valus gives infinity
	for (i=0; i< i_Max; ++i ){
		z=z*z +c; 
	 
	 }
	 
	 return cabs(z);
	
	
}


Another way: choose the parameter c such that it is on an escape line, then the critical value will be on an escape line as well.

Inner radiusEdit

Inner radius of Siegel Disc

  • radius of inner circle, where inner circle with center at fixed point is the biggest circle inside Siegel Disc.
  • minimal distance between center of Siel Disc and critical orbit

Internal radiusEdit

Internal radius is a:

  • absolute value of multiplier  


See also: the N-2 rule[252]

SequencesEdit

A sequence is an ordered list of objects (or events).[253]

A series is the sum of the terms of a sequence of numbers.[254] Some times these names are not used as in above definitions.


ItineraryEdit

  is an itinerary of point x under the map f relative to the paritirtion.

It is a right-infinite sequence of zeros and ones [255]

  

where

Examples:

For rotation map   and invariant interval   (circle):

 

one can compute  :

  

and split interval into 2 subintervals (lower circle partition):

 

 

then compute s according to it's relation with critical point:

 

Itinerary can be converted[256] to point  

 


kneading sequenceEdit

  • "the kneading sequence of an external angle ϑ (here ϑ = 1/6) is defined as the itinerary of the orbit of ϑ under angle doubling, where the itinerary is taken with respect to the partition formed by the angles ϑ/2, and (ϑ + 1)/2 "[257]
  • The itinerary ν = ν1ν2ν3 . . . of the critical value is called the kneading sequence.[258] One can start from the critical point but neglect the initial symbol. Such sequence is computed with the Hubbard tree


See also:

Thue–Morse sequenceEdit

Thue–Morse sequence

OrbitEdit

Orbit can be:

  • forward = sequence of points
  • backward (inverse)
    • tree in case of multivalued function
    • sequence

SeriesEdit

A series is the sum of the terms of a sequence of numbers.[260] Some times these names are not used as in above definitions.

TaylorEdit

  • Taylor series and Mandelbrot set[261]
  • The Existence and Uniqueness of the Taylor Series of Iterated Functions [262]

SetEdit

Attracting setEdit

Informal definition:

  "an attracting set for a dynamical system is a closed subset A of its phase space such that for "many" choices of initial point the system will evolve towards A ." John W Milnor[263]

ContinuumEdit

definition[264]


BandEdit

chaotic bandEdit

Chaotic bands from B0 to B10



period-  chaotic band  [265]

  • is between Misiurewicz points (primary separators)   and  
  • it's biggest midget has period  
  • contains Sharkovsky subsequence: sequence of islands for periods:   for k = 1, 2, ..... (in the increasing order = increasing from left to right). These are first appearance of hyperbolic components with such period in Sharkowsky ordering
  • is on n-place in Sharkowsky ordering


 
 
 


 


Dwell bandsEdit

"Dwell bands are regions where the integer iteration count is constant, when the iteration count decreases (increases) by 1 then you have passed a dwell band going outwards (inwards). " [266] Other names:

  • level sets of integer escape time

BasinEdit

Basin can consist of

  • one component, like basin of infinity

of attractionEdit

definitions:

  • An attractor's basin of attraction is the region of the phase space, over which iterations are defined, such that any point (any initial condition) in that region will asymptotically be iterated into the attractor
  • The collection of all points whose iterates under f converge to the attractor [267]


immediate basin of attractionEdit

the component of the basin containing the periodic point itself

Examples

  • basin of infinity (whole basin = one component)


 

ComponentEdit

connected component (blob) in the imageEdit

Components of parameter planeEdit

Names:

  • mu-atom[268]
  • ball
  • bud
  • bulb
  • decoration: "A decoration of the Mandelbrot set M is a part of M cut off by two external rays landing at some tip of a satellite copy of M attached to the main cardioid."[269]
  • lake
  • lakelet.[270]


filamentEdit

from Mu-Ency: "Any contiguous subset of the Mandelbrot Set which consists of the infinitely convoluted and branching structures that connect the island mu-molecules to each other."

Some colloquial names for filaments:

  • antenna
    • main antenna
  • spike
  • spoke.
 "A filament consists of a) minibrots and b) limit points of sequences of those minibrots. The latter include Misiurewicz points (rational external angles, one for filament termini and two or more for interior points such as multi-armed spiral centers) and other points (with irrational external angles).
 My intuition says if you zoom to a succession of smaller minis along a filament, if this is done in a pattern for infinitely long you tend to a Misiurewicz point, and if it's done randomly for infinitely long you tend to an irrational point. But I have no proof of this. 
 Other noninterior points on filaments mostly belong to individual minibrots: cardioid cusps (two rational external angles, odd denominator) and minibrot-filament branch tips (Misiurewicz points, two rational external angles, even denominator). 
 There is one last point: the exact base of the filament where it attaches to something (minibrot or main set). This point has irrational external angles. The Feigenbaum point at the base of the spike is one of these." pauldelbrot[271]

IslandsEdit

Names:

  • mini Mandelbrot set
  • 'baby'-Mandelbrot set
  • island mu-molecules = embedded copy of the Mandelbrot Set[272]
  • Bug
  • Island
  • Mandelbrotie
  • Midget

List of islands:


features of island

  • period
  • symbolic sequence
  • angled internal address
  • lower and upper external angle of rays landing on it's root
  • center (
  • root
  • orientation
  • size
  • distortion
  • tip (Misiurewicz point,
    • c value
    • period and preperiod
    • lower and upper external angle of rays landing on it

Primitive and satelliteEdit

"Hyperbolic components come in two kinds, primitive and satellite, depending on the local properties of their roots." [273]

  • primitive (non-satellite)
    • the root of component is not on the boundary of another component = "it was born from another hyperbolic component by the period increasing bifurcation"[274]
    • ones that have a cusp likes the main cardioid, when the little Julia sets are disjoint [275]
  • satellite
    • ones that don't have a cusp[276]
    • it's root is on the boundary of another hyperbolic component [277]
    • when the little Julia sets touch at their β-fixed point

primareEdit

Child (Descendant) and the parent (ancestor)Edit

  • ancestor of hyperbolic component
  • descendant of hyperbolic component = child [278]

Hyperbolic component of Mandelbrot setEdit

 
Boundaries of hyperbolic components of Mandelbrot set

Domain is an open connected subset of a complex plane.

"A hyperbolic component H of Mandelbrot set is a maximal domain (of parameter plane) on which   has an attracting periodic orbit.

A center of a H is a parameter   (or point of parameter plane) such that the corresponding periodic orbit has multiplier= 0." [279]

A hyperbolic component is narrow if it contains no component of equal or lesser period in its wake [280]

features of hyperbolic component

  • period
  • islandhood (shape = cardiod or circle)
  • angled internal address
  • lower and upper external angle of rays landing on it's root
  • center (
  • root
  • orientation
  • size


Abreviations:

  • LAHCs = the last appearance HCs placed in the chaotic region

LimbEdit

  • The part of the Mandelbrot set contained in the wake together with the root   is called the limb   of the Mandelbrot set originated at H (hyperbolic component of the Mandelbrot set)[281]
 
13/34 limb and wake on the left image

p/q-limb is a part of Mandelbrot set contained inside p/q-wake

For every rational number  , where p and q are relatively prime, a hyperbolic component of period q bifurcates from the main cardioid. The part of the Mandelbrot set connected to the main cardioid at this bifurcation point is called the p/q-limb. Computer experiments suggest that the diameter of the limb tends to zero like  . The best current estimate known is the Yoccoz-inequality, which states that the size tends to zero like  .

A period-q limb will have q − 1 "antennae" at the top of its limb. We can thus determine the period of a given bulb by counting these antennas.

In an attempt to demonstrate that the thickness of the p/q-limb is zero, David Boll carried out a computer experiment in 1991, where he computed the number of iterations required for the series to converge for z =   (  being the location thereof). As the series doesn't converge for the exact value of z =  , the number of iterations required increases with a small ε. It turns out that multiplying the value of ε with the number of iterations required yields an approximation of π that becomes better for smaller ε. For example, for ε = 0.0000001 the number of iterations is 31415928 and the product is 3.1415928.[282]

Types:[283]

  • The limbs attached to the main cardioid are called primary.
  • Let H be a hyperbolic component attached to the main cardioid. The limbs attached to such a component are called secondary
  • We refer to a truncated limb if we remove from it a neighborhood of its root

moleculeEdit

  • The main molecule is the union of all hyperbolic components attached to the main cardioid through a chain of finitely many components.[284]
  • island mu-molecule = island mu-unit [285]

shrubEdit

  • "what emerges from Myrrberg-Feigenbaum point is what we denominate a shrub due to its shape" M Romera
  • filament,
  • chaotic part of the p/q limb: "The chaotic region is made up of an infinity of hyperbolic components mounted on an infinity of shrub branches in each one of the infinity shrubs of the family."[286]

Examples

  • main antenna is a shrub of   family

spokesEdit

"Colloquial term for a filament, specifically one of the "arms" radiating from a branch point." - from Mu-Ency

WakeEdit

 
Wakes of Mandelbrot Set to Period 10

p/q-wake is the region of parameter plane enclosed by two external rays landing on the same root point on the boundary of main cardioid (period 1 hyperbolic component).

Angles of the external rays that land on the root point one can find by:

p/q-Subwake of W is a wake of a p/q-satellite component of W

 
Wake 1/3 (bounded by 2 external rays) and internal ray 1/3

wake is named after:

  • rotation number p/q (as above)
  • angles of external rays landing in it's root point: "If two M-rays   land at the same point   we denote by wake   the component of   which does not contain 0."[287]

Components of dynamical planeEdit

In case of Siegel disc critical orbit is a boundary of component containing Siegel Disc.


For a quadratic polynomial with a parabolic orbit, the unique Fatou component[288] containing the critical value will be called the characteristic Fatou component; (Dierk Schleicher in Rational Parameter Rays of the Mandelbrot Set)

 "for rational maps (iterating maps of the form f(x)=p(x)/q(x) where p,q are polynomials) result in 1, 2 or infinitely many components."[289]


See also:

  • interior and exterior of filled Julia set for polynomials
  • immediate basin of attraction

DomainEdit

Domain in mathematical analysis it is an open connected set

Jordan domainEdit

"A Jordan domain[290] J is the homeomorphic image of a closed disk in E2. The image of the boundary circle is a Jordan curve, which by the Jordan Curve Theorem separates the plane into two open domains, one bounded, the other not, such that the curve is the boundary of each." [291]

Examples:

FlowerEdit

Lea-Fatu flower

IntervalEdit

a partition of an interval into subintervals

InvariantEdit

sth is invariant if it does't change under transformation

"A subset S of the domain Ω is an invariant set for the system (7.1) if the orbit through a point of S remains in S for all t ∈ R. If the orbit remains in S for t > 0, then S will be said to be positively invariant. Related definitions of sets that are negatively invariant, or locally invariant, can easily be given" [293]

Examples:

  • invariant set
  • invariant point = fixed point
  • invariant cycle = periodic point
  • invariant curve
    • invariant circle
  • petal = invariant planar set

Julia setEdit

Feigenbaum Julia setEdit

Julia set for Feigenbaum parameter c

Successive zooms lead to a Julia set which grows more and more hairs. (Similarly, the Mandelbrot set gains more decorations while limiting on the Feigenbaum point.)
This leads to the natural question: Does the Julia set of the Feigenbaum quadratic polynomial have positive or zero measure?
If zero, is its Hausdorff dimension less than 2?[294]

Level setEdit

in case of:

attracting caseEdit

On the dynamic plane level set is defined:

 

Boundaries of level sets (lemniscates) are

     


On the parameter plane

 

where

  •   is Escape Radius, bailout value, radius of circle which is used to measure if orbit of   is bounded; it is integer number
  •   are complex numbers (points of 2-D planes)
  •   is point of dynamical plane (z-plane)
  •   is point of parameter plane (c-plane)
  •  
  •  
  •  
  •   critical point of  

Then:

 

 

 

...

  is a circle,

  is an Cassini oval,

  is a pear curve[296][297].

These curves tend to boundary of Mandelbrot set as n goes to infinity.

  • If ER < 2 they are inside Mandelbrot set[298].
  • If ER = 2 curves meet together (have common point) c = −2. Thus they can't be equipotential lines.
  • If ER ≥ 2 they are outside of Mandelbrot set. They can also be drawn using Level Curves Method.
  • If ER >> 2 they approximate equipotential lines (level curves of real potential, see CPM/M).


parabolic caseEdit

 

Where:

  • d is a diameter of circle
    • through 2 points:   and  
    • radius r is half of diameter:  
  •   is n*p iteration of critical point
  • fixed point of p iteration of f function  
  • p is a period of the cycle

LocusEdit

CantorEdit

The Cantor locus is the unique hyperbolic component, in the moduli space of quadratic rational maps rat2, consisting of maps with totally disconnected Julia sets [299]

ConnectednessEdit

In one-dimensional complex dynamics, the connectedness locus is a subset of the parameter space of rational functions, which consists of those parameters for which the corresponding Julia set is connected. the Mandelbrot set is a subset of the complex plane that may be characterized as the connectedness locus of a family of polynomial maps.

Planar setEdit

a non-separating planar set is a set whose complement in the plane is connected.[300]



postsingularEdit

"The postsingular set P(f) of a meromorphic function f is the closure of the union of forward iterates of the singular set S(f):"[301]


 

post-criticalEdit

  • the iterates of the critical set
  • "For a rational map of the Riemann sphere f, the post-critical set PC(f) is defined as closure of orbits of all critical points of f. It is proved by Lyubich [Ly83b] that the post-critical set of a rational map is the measure theoretic attractor of points in the Julia set of that map. That is, for every neighborhood of the post-critical set, orbit of almost every point in the Julia set eventually stays in that neighborhood" [302]
  • "The postcritical set P(f) of a rational map f is the smallest forward invariant subset of that contains the critical values of f."[303]
  • "The analysis of the post-critical set plays a central role in the dynamics of rational maps, mainly because of the following two properties:
    • the set of attracting cycles is always finite for rational maps f
    • every attracting cycle attracts the orbit of a critical point of f."[304]

regionEdit

SepalEdit

Sepal


Singular setEdit

"The singular set S(f) of a meromorphic function f : C → Cˆ is the collection of values w at which one can not define all branches of the inverse f −1 in any neighborhood of w. If f is rational, then S(f) coincides with the collection of critical values of f. If f is transcendental meromorphic, f −1 may also fail to be defined in a neighborhood of an asymptotic value" [306]

Target setEdit

Target set

  • trap for forward orbit
  • it is a set which captures any orbit tending to fixed / periodic point

TrapEdit

Trap is another name of the target set

TestEdit

Bailout test or escaping testEdit

 
Two sets after bailout test: escaping white and non-escaping black
 
Distance to fixed point for various types of dynamics

It is used to check if point z on dynamical plane is escaping to infinity or not.[307] It allows to find 2 sets:

  • escaping points (it should be also the whole basing of attraction to infinity)[308]
  • not escaping points (it should be the complement of basing of attraction to infinity)

In practice for given IterationMax and Escape Radius:

  • some pixels from set of not escaping points may contain points that escape after more iterations then IterationMax (increase IterMax)
  • some pixels from escaping set may contain points from thin filaments not choosed by maping from integer to world (use DEM)

If   is in the target set   then   is escaping to infinity (bailouts) after n forward iterations (steps).[309]

The output of test can be:

  • boolean (yes/no)
  • integer: integer number (value of the last iteration)

Types of bailout test:

CriterionEdit

criterion = an algorithm which will always give an answer

Attraction testEdit

TheoremEdit

  • The Douady-Hubbard landing theorem for periodic external rays of polynomial dynamics: "for a complex polynomial f with bounded postcritical set, every periodic external ray lands at a repelling or parabolic periodic point, and conversely every repelling or parabolic point is the landing point of at least one periodic external ray." [310]

ReferencesEdit

  1. haskell package: ruff-0.2by Claude Heiland-Allen
  2. On the Locus of Crossed Renormalization (Problems on complex dynamical systems) by Riedl, Johannes; Schleicher, Dierk
  3. Trees of visible components in the Mandelbrot set by Virpi K a u k o
  4. Rational Maps with Clustering and the Mating of Polynomials by Thomas Joseph Sharland
  5. analytical naming system From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2020.  
  6. math.stackexchange question: naming-bulbs-on-the-mandelbrot-set
  7. Topics from One-Dimensional Dynamics by Karen M. Brucks,Henk Bruin. page 265 exercise 14.2.12
  8. muency - internal angle (the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2016.)
  9. internal angle from the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2017
  10. argument of complex number
  11. A Method to Solve the Limitations in Drawing External Rays of the Mandelbrot Set M. Romera, G. Pastor, A. B. Orue, A. Martin, M.-F. Danca, and F. Montoya
  12. Matcont - is a Matlab software project for the numerical continuation and bifurcation study of continuous and discrete parameterized dynamical systems. Leaders of the project are Willy Govaerts (Gent,B) and Yuri A. Kuznetsov (Utrecht,NL).
  13. quora: What-is-gradient?
  14. geometry by Dr. Carol JVF Burns
  15. What is a Curve  ?
  16. Unit circle in Wikipedia
  17. The Road to Chaos is Filled with Polynomial Curves by Richard D. Neidinger and R. John Annen III. American Mathematical Monthly, Vol. 103, No. 8, October 1996, pp. 640-653
  18. Hao, Bailin (1989). Elementary Symbolic Dynamics and Chaos in Dissipative Systems. World Scientific. ISBN 9971-5-0682-3. http://power.itp.ac.cn/~hao/. 
  19. M. Romera, G. Pastor and F. Montoya, "Misiurewicz points in one-dimensional quadratic maps", Physica A, 232 (1996), 517-535. Preprint
  20. LAMINATIONAL MODELS FOR SOME SPACES OF POLYNOMIALS OF ARBITRARY DEGREE by ALEXANDER BLOKH, LEX OVERSTEEGEN, ROSS PTACEK, AND VLADLEN TIMORIN
  21. Models_for_spaces_of_dendritic_polynomials by ALEXANDER BLOKH, LEX OVERSTEEGEN, ROSS PTACEK,AND VLADLEN TIMORIN
  22. MODELING DENDRITIC SHAPES Using Path Planning by Ling Xu, David Mould
  23. procedural-branching-texture in blender by LordoftheFleas
  24. Escape lines versus equipotential lines in the Mnadelbrot set by M. Romera, Pastor G, D. de la Guía, Montoya
  25. Pseudosphere Geodesics by Tim Hutton
  26. The Computation of Invariant Circles of Maps Article in Physica D Nonlinear Phenomena 16(2):243-251 · June 1985 DOI: 10.1016/0167-2789(85)90061-2 1st I.G. Kevrekidis
  27. A Newton-Raphson method for numerically constructing invariant curves Marty, Wolfgang
  28. Numerical Approximation of Rough Invariant Curves of Planar Maps Article in SIAM Journal on Scientific Computing 25(1) · September 2003 DOI: 10.1137/S106482750241373X K. D. Edoh and Jens Lorenz
  29. SIAM J. Sci. and Stat. Comput., 8(6), 951–962. (12 pages) A New Algorithm for the Numerical Approximation of an Invariant Curve Published online: 14 July 2006 Keywords invariant manifold, polygonal approximation AMS Subject Headings 65L99, 65H10, 34C40 Publication Data ISSN (print): 0196-5204 ISSN (online): 2168-3417 Publisher: Society for Industrial and Applied Mathematics M. van Veldhuizen
  30. ON QUASI-INVARIANT CURVES by RICARDO PEREZ-MARCO
  31. Escape lines versus equipotential lines in the Mnadelbrot set by M. Romera, Pastor G, D. de la Guía, Montoya
  32. Wikipedia: Jordan curve theorem
  33. Modeling Julia Sets with Laminations: An Alternative Definition by Debra Mimbs
  34. Laminations of the unit disk with irrational rotation gaps by John C. Mayer
  35. Rational maps represented by both rabbit and aeroplane matings Thesis submitted in accordance with the requirements of the University of Liverpool for the degree of Doctor in Philosophy by Freddie R. Exall July 2010
  36. Core entropy and biaccessibility of quadratic polynomials by Wolf Jung
  37. Rational maps represented by both rabbit and aeroplane matings Thesis submitted in accordance with the requirements of the University of Liverpool for the degree of Doctor in Philosophy by Freddie R. Exall July 2010
  38. Rational Parameter Rays of the Mandelbrot Set by Dierk Schleicher
  39. Critical portraits for postcritically finite polynomials by Alfredo Poirier
  40. NON-ACCESSIBLE CRITICAL POINTS OF CERTAIN RATIONAL FUNCTIONS WITH CREMER POINTS by Lia Petracovici
  41. Convergence of external rays in parameter spaces of symmetric polynomials by Ahmad Zireh. Int. J. Contemp. Math. Sciences, Vol. 2, 2007, no. 6, 291 - 296
  42. A survey on MLC, Rigidity and related topics by Anna Miriam Benini
  43. Local Connectivity of the Mandelbrot Set. by Matt Koster December 4, 2019
  44. Critical portraits for postcritically finite polynomials by Alfredo Poirier
  45. Graph Replacement Systems for Julia Sets of Quadratic Polynomials by Yuan J. Liu
  46. wikipedia: Filled_Julia_set
  47. Rational Parameter Rays of The Multibrot Sets by Dominik Eberlein, Sabyasachi Mukherjee, Dierk Schleicher
  48. Robert L. Devaney. "Intertwined internal rays in Julia sets of rational maps." Fundamenta Mathematicae 206.1 (2009): 139-159. <http://eudml.org/doc/283146>.
  49. Iterated Monodromy Groups of Quadratic Polynomials, I Laurent Bartholdi, Volodymyr V. Nekrashevych
  50. GROWTH OF GROUPS DEFINED BY AUTOMATA: ASHLEY S. DOUGHERTY, LYDIA R. KINDELIN, AARON M. REAVES, ANDREW J. WALKER, AND NATHANIEL F. ZAKAHI
  51. Douglas C. Ravenel: External angles in the Mandelbrot set: the work of Douady and Hubbard. University of Rochester Template:Webarchive
  52. John Milnor: Pasting Together Julia Sets: A Worked Out Example of Mating. Experimental Mathematics Volume 13 (2004)
  53. Saaed Zakeri: Biaccessiblility in quadratic Julia sets I: The locally-connected case
  54. A. Douady, “Algorithms for computing angles in the Mandelbrot set,” in Chaotic Dynamics and Fractals, M. Barnsley and S. G. Demko, Eds., vol. 2 of Notes and Reports in Mathematics in Science and Engineering, pp. 155–168, Academic Press, Atlanta, Georgia, USA, 1986.
  55. K M. Brucks, H Bruin: Topics from One-Dimensional Dynamics Series: London Mathematical Society Student Texts (No. 62) page 257
  56. The applications of non-euclidean distance | Metric Spaces by Zach Star
  57. distance fields by Philip Rideout
  58. Distance Transforms of Sampled Functions by Pedro Felipe Felzenszwalb
  59. dsp.stackexchange question: fastest-algorithm-for-distance-transform
  60. Symbolic Dynamics of Quadratic Polynomials by H. Bruin and D. Schleicher
  61. Symbolic Dynamics and Rotation Numbers J. J. P. Veerman Phys. 13A, 1986, 543-576.
  62. Symbolic Dynamics of Order-Preserving Orbits J. J. P. Veerman Phys. 29D, 1987, 191-201.
  63. Walter Bergweiler: A gallery of complex dynamics pictures.
  64. Around the boundary of complex dynamics by Roland K. W. Roeder
  65. Image entropy by Dave O'Brien
  66. fractal-rendering from cglearn
  67. mathoverflow question: whats-a-natural-candidate-for-an-analytic-function-that-interpolates-the-tower/43003
  68. Faa di Bruno and derivatives of an iterated function ON MAY 20, 2017 BY DCHOYLE
  69. A Cheritat wiki: Mandelbrot_set - Following_the_derivative
  70. Shapiro, J.H. (1993). The Angular Derivative. In: Composition Operators. Universitext: Tracts in Mathematics. Springer, New York, NY. https://doi.org/10.1007/978-1-4612-0887-7_5
  71. MAT335H1F Lecture Notes by Burbulla (Chapter 11, 12 and 13)
  72. Schwarzian-Derivative-Poster
  73. Schwarzian derivatives of rational functions by Alex Eremenko
  74. What is ... Schwarzian Derivative? (Notices of AMS Jan 2009),
  75. betterexplained: vector-calculus-understanding-the-gradient
  76. khan academy: the-gradient
  77. Gradient-Based Optimization by Jason Hicken, Prof. Juan Alonso, and Prof. Charbel Farhat
  78. gradient-descent-algorithm-and-its-variants by Imad Dabbura
  79. The chaotic nature of faster gradient descent methods by Kees van den Doel and Uri Ascher
  80. Conformal Geometry and Dynamics of Quadratic Polynomials, vol I-II Mikhail Lyubich, page 61
  81. Germ in wikipedia
  82. Linearization of germs: regular dependence on the multiplier by Carlo Carminati, Stefano Marmi
  83. math.stackexchange question: is-there-any-difference-between-mapping-and-function
  84. Iterated function (map) in wikipedia
  85. evolution function
  86. the discrete nonlinear dynamical system
  87. math.stackexchange question: why-is-local-connectivity-important-for-polynomial-julia-sets
  88. riemann-for-anti-dummies by the LaRouche Youth Movement in Canada
  89. chebfun docs
  90. HarmonicFunction by (c) 2011 John H. Mathews, Russell W. Howell
  91. Connectivity of Julia sets of Newton maps: A unified approach by K. Baranski N. Fagella X. Jarque B. Karpinska
  92. A Beginners’ Guide to Resurgence and Trans-series in Quantum Theories Gerald Dunne
  93. A Primer on Resurgent Transseries and Their Asymptotics by Inês Aniceto, Gökçe Başar, Ricardo Schiappa
  94. Universality of Resurgence in Quantization Theories - video
  95. Olexandr Ganyushkin; Volodymyr Mazorchuk (2008). Classical Finite Transformation Semigroups: An Introduction. Springer Science & Business Media. p. 1. ISBN 978-1-84800-281-4. https://archive.org/details/classicalfinitet00gany_719. 
  96. Pierre A. Grillet (1995). Semigroups: An Introduction to the Structure Theory. CRC Press. p. 2. ISBN 978-0-8247-9662-4. https://books.google.com/books?id=yM544W1N2UUC&pg=PA2. 
  97. Wilkinson, Leland & Graham (2005). The Grammar of Graphics (2nd ed.). Springer. p. 29. ISBN 978-0-387-24544-7. https://books.google.com/books?id=NRyGnjeNKJIC&pg=PA29. 
  98. "Transformations". https://www.mathsisfun.com/geometry/transformations.html. 
  99. "Types of Transformations in Math". https://www.basic-mathematics.com/transformations-in-math.html. 
  100. dinkydauset at deviantar: Perturbation-for-the-Mandelbrot-set-450766847
  101. math.stackexchange question: selecting-reference-orbit-for-fractal-rendering-with-perturbation-theory
  102. math.stackexchange question: coloring-the-mandelbrot-set-using-iterated-points?
  103. Dessins d’enfants and Hubbard trees by Kevin M. Pilgrim
  104. Admissibility of kneading sequences and structure of Hubbard trees for quadratic polynomials by Henk Bruin, Dierk Schleicher
  105. wikipedia: Magnitude in mathematics
  106. Hyperbolic Components by John Milnor
  107. Complex quadratic map in wikipedia
  108. Michael Yampolsky, Saeed Zakeri: Mating Siegel quadratic polynomials.
  109. Mandel: software for real and complex dynamics by Wolf Jung
  110. three-cool-facts-about-rotations-of-the-circle by David Richeson
  111. irrational-rotations-of-the-circle-and-benfords-law by David Richeson
  112. The measure of the Feigenbaum Julia set by Artem Dudko and Scott Sutherland
  113. Poincaré map
  114. General principles of chaotic dynamics by P.B. Persson, C.D. Wagner
  115. Continuous time and discrete time dynamical systems by Shaun Bullett
  116. Continuous time and discrete time dynamical systems by Shaun Bullett
  117. EXPONENTIAL THURSTON MAPS AND LIMITS OF QUADRATIC DIFFERENTIALS by JOHN HUBBARD, DIERK SCHLEICHER, AND MITSUHIRO SHISHIKURA
  118. The Thurston Algorithm for quadratic matings by Wolf Jung
  119. Conformal Geometry and Dynamics of Quadratic Polynomials Mikhail Lyubich
  120. wikipedia: Riemann mapping theorem
  121. A THOMPSON GROUP FOR THE BASILICA by JAMES BELK AND BRADLEY FORREST
  122. math stackexchange question: explicit-riemann-mappings
  123. mathoverflow question: complex-function-for-mapping-a-circle-to-a-superellipse
  124. math.stackexchange question: explicit-riemann-mappings
  125. Dynamics of quadratic polynomials, I: Combinatorics and geometry of the Yoccoz puzzle by Mikhail Lyubich
  126. A THOMPSON GROUP FOR THE BASILICA by JAMES BELK AND BRADLEY FORREST
  127. Graph Replacement Systems for Julia Sets of Quadratic Polynomials by Yuan J. Liu
  128. A Thompson-Like Group for the Bubble Bath Julia Set by Jasper Weinrich-Burdref
  129. three-cool-facts-about-rotations-of-the-circle by David Richeson
  130. binary_shift_left
  131. Feigenbaum constants
  132. Degree in Wikipedia (disambiguation page)
  133. fractalforums.org: definitions-of-degree-of-rational-function
  134. Multiplier at wikipedia
  135. Internal angles and multipliers from Fractal Geometry Yale University Michael Frame, Benoit Mandelbrot (1924-2010), and Nial Neger September 3, 2017
  136. A Cheritat wiki-draw: Mandelbrot_set#Following_the_derivative
  137. scholarpedia: Siegel disks Linearization
  138. Periodic cycles and singular values of entire transcendental functions by Anna Miriam Benini and Nuria Fagella
  139. Wikipedia: Rotation number
  140. rotation number From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2016
  141. scholarpedia: Rotation_theory
  142. The Fractal Geometry of the Mandelbrot Set II. How to Count and How to Add Robert L. Devaney
  143. An Introduction to Rotation Theory Prize winner, DSWeb Student Competition, 2007 By Christian Kue
  144. Complex systems simulation Curso 2012-2013 by Antonio Giraldo and María Asunción Sastre
  145. Weisstein, Eric W. "Map Winding Number." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/MapWindingNumber.html
  146. Wikipedia: Rotation number
  147. RATIONAL PARAMETER RAYS OF THE MANDELBROT SET by Dierk Schleicher
  148. https://plus.maths.org/content/winding-numbers-topography-and-topology-ii
  149. Winding-Number by empet
  150. Finding the number of roots of a polynomial in a plane region using the winding number by Juan Luis García Zapataa, Juan Carlos Díaz Martín
  151. MATH 145: SUPPLEMENTARY NOTES by VIN DE SILVA
  152. Wikipedia: Orbit (dynamics)
  153. Ouadratic-like maps and Renormalization by Nuria Fagella
  154. Peiod From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2015.
  155. scholarpedia: Periodic Orbit for a Map
  156. Wikipedia: Complex quadratic polynomial - Planes
  157. N-sphere in wikipedia
  158. UC San Diego : MATH 196/296: Student Colloquium
  159. math.stackexchange question: entire-function-with-image-contained-in-slit-plane-is-constant
  160. Alternate Parameter Planes by David E. Joyce
  161. mu-ency: exponential map by R Munafo
  162. Exponential mapping and OpenMP by Claude Heiland-Allen
  163. Linas Vepstas : Self Similar?
  164. the flattened cardioid of a Mandelbrot by Tom Rathborne
  165. Stretching cusps by Claude Heiland-Allen
  166. Twisted Mandelbrot Sets by Eric C. Hill
  167. doubling bifurcations on complex plane by E Demidov
  168. On biaccessible points in the Julia set of the family z(a+z^{d}) by Mitsuhiko Imada
  169. Campbell, J.T., Collins, J.T. Blowup Points and Baby Mandelbrot Sets for a Family of Singularly Perturbed Rational Maps. Qual. Theory Dyn. Syst. 16, 31–52 (2017). https://doi.org/10.1007/s12346-015-0169-5
  170. Topological Variety of Buried Points by Clinton P. Curry, Logan C. Hoehn, and John C. Mayer
  171. Surgery in Complex Dynamics by Carsten Lunde Petersen, online paper
  172. Nucleus - From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2015.
  173. Siegel disks by Xavier Buff and Arnaud Ch ́ritat e Univ. Toulouse Roma, April 2009
  174. Wikipedia: Critical point (mathematics)
  175. Java program by Dieter Röß showing result of changing initial point of Mandelbrot iterations
  176. Cut point in wikipedia
  177. On local connectivity for the Julia set of rational maps: Newton’s famous example By P. Roesch
  178. muency: feigenbaum point
  179. On Periodic and Chaotic Regions in the Mandelbrot Set by G. Pastor, M. Romera, G. Álvarez, D. Arroyo and F. Montoya
  180. fractal-faq : section 6
  181. Period doubling and Feigenbaum's scaling be E Demidov
  182. mathoverflow question: is-there-a-way-to-find-regions-of-depth-in-the-mandelbrot-set-other-than-simply?rq=1
  183. Fractalforums: fibonacci-and-the-mandelbrot-set
  184. Parameter scaling for the Fibonacci point by Leroy Wenstrom
  185. The Fibonacci unimodal map by Mikhail Lyubich, John W. Milnor
  186. [w:Point at infinity|Point at infinity in wikipedia]
  187. Mathoverflow question: Attractive Basins and Loops in Julia Sets
  188. Wikipedia: Misiurewicz point
  189. The bifurcation diagram of cubic polynomial vector fields on CP1 by Christiane Rousseau
  190. A rigidity result for some parabolic germs by Luna Lomonaco, Sabyasachi Mukherjee
  191. http://www.mndynamics.com/indexp.html%7C program Mandel by Wolf Jung, demo 2 page 3
  192. Thompson-Like Groups for Dendrite Julia Sets by Will Smith
  193. GROWTH OF GROUPS DEFINED BY AUTOMATA : ASHLEY S. DOUGHERTY, LYDIA R. KINDELIN, AARON M. REAVES, ANDREW J. WALKER, AND NATHANIEL F. ZAKAHI
  194. Ouadratic-like maps and Renormalization by Nuria Fagella
  195. mathoverflow question: is-there-a-way-to-find-regions-of-depth-in-the-mandelbrot-set-other-than-simply?rq=1
  196. Immediate renormalization of complex polynomials by Alexander Blokh, Lex Oversteegen, Vladlen Timorin
  197. Buff, Xavier. "Virtually repelling fixed point.." Publicacions Matemàtiques 47.1 (2003): 195-209. <http://eudml.org/doc/41482>.
  198. Bond the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2018.
  199. Wikipedia: Orbit portrait
  200. THURSTON’S ALGORITHM AND RATIONAL MAPS FROM QUADRATIC POLYNOMIAL MATINGS by Mary Wilkerson
  201. stackoverflow question: how-do-i-interpret-precision-and-scale-of-a-number-in-a-database
  202. taking-the-error-out-of-the-error-function by Fredrik Johansson
  203. An Introduction To Small Divisors by S. Marmi
  204. scholarpedia: Siegel disks Linearization
  205. serious_statistics_aliasing by GuestJim
  206. Arnold V. I. Geometric Methods in the Theory of Ordinary Differential Equations (Springer, 2020) [1]
  207. Alligood, K. T., Sauer, T., and Yorke, J.A. (1997). Chaos: An Introduction to Dynamical Systems. Springer. pp. 114–124. ISBN 0-387-94677-2. 
  208. Devaney, R.; Nitecki, Z. (1979). "Shift automorphisms in the Hénon mapping". Comm. Math. Phys. 67 (2): 137–146. doi:10.1007/bf01221362. Bibcode1979CMaPh..67..137D. https://projecteuclid.org/euclid.cmp/1103905161. Retrieved 2 September 2016. 
  209. Digital_image_processing in wikipedia
  210. autodiff.org
  211. Wikipedia: Numerical_differentiation
  212. Numerical Recipies In C : 5.7 Numerical Derivatives
  213. stackoverflow question: is-there-any-standard-way-to-calculate-the-numerical-gradient
  214. Wikipedia: Finite difference
  215. Wikipedia: discretization
  216. mathinsight: from_discrete_to_continuous_dynamical_systems
  217. J.M. Hyman, M. Shashkov, Natural discretizations for the divergence, gradient, and curl on logically rectangular grids, Computers & Mathematics with Applications, Volume 33, Issue 4, 1997, Pages 81-104, ISSN 0898-1221, https://doi.org/10.1016/S0898-1221(97)00009-6. (https://www.sciencedirect.com/science/article/pii/S0898122197000096) Abstract: This is the first in series of papers creating a discrete analog of vector analysis on logically rectangular, nonorthogonal, nonsmooth grids. We introduce notations for 2-D logically rectangular grids, describe both cell-valued and nodal discretizations for scalar functions, and construct the natural discretizations of vector fields, using the vector components normal and tangential to the cell boundaries. We then define natural discrete analogs of the divergence, gradient, and curl operators based on coordinate invariant definitions and interpret these formulas in terms of curvilinear coordinates, such as length of elements of coordinate lines, areas of elements of coordinate surfaces, and elementary volumes. We introduce the discrete volume integral of scalar functions, the discrete surface integral, and a discrete analog of the line integral and prove discrete versions of the main theorems relating these objects. These theorems include the following: the discrete analog of relationship div A→ = 0 if and only if A→ = curl B→; curl A→ = 0 if and only if A→ = grad ϕ; if A→ = grad ϕ, then the line integral does not depend on path; and if the line integral of a vector function is equal to zero for any closed path, then this vector is the gradient of a scalar function. Last, we define the discrete operators DIV, GRAD, and CURL in terms of primitive differencing operators (based on forward and backward differences) and primitive metric operators (related to multiplications of discrete functions by length of edges, areas of surfaces, and volumes of 3-D cells). These formulations elucidate the structure of the discrete operators and are useful when investigating the relationships between operators and their adjoints. Keywords: Finite-difference; Logically-rectangular grids; Discrete vector analysis
  218. filterforge filters: distorsion
  219. Airplane primitive parabolic implosion by Wolf Jung
  220. Parabolic Implosion by Han Peters, L. Vivas Published 2020
  221. SemiParabolicImplosion by Eric Bedford
  222. CANTOR BOUQUETS, EXPLOSIONS, AND KNASTER CONTINUA: DYNAMICS OF COMPLEX EXPONENTIALS by Robert L. Devaney Publicacions Matematiques, Vol 43 (1999), 27–54.
  223. fractalforums.com: smooth-external-angle-of-mandelbrot-set
  224. Jean-Christophe Yoccoz Small Divisors: Number Theory in Dynamical Systems, page 46
  225. Integrability and Linearizability of the Lotka^Volterra System with a Saddle Point with Rational Hyperbolicity Ratio by Simon Gravel and Pierre Thibault
  226. On The Notions of Mating by Carsten Lunde Petersen, Daniel Meyer
  227. Normal Forms, Bifurcations and Finiteness Problems in Differential Equations by Yulij Ilyashenko, Christiane Rousseau, Gert Sabidussi
  228. towardsdatascience: gradient-descent-algorithm-and-its-variants
  229. math.stackexchange question: what-is-parameterization
  230. Perturbation for the Mandelbrot set by DinkydauSet, Apr 28, 2014, 3:46:13 PM
  231. PARABOLIC IMPLOSION A MINI-COURSE ARNAUD CHERITAT
  232. wikipedia: Approximation error
  233. Baby Mandelbrot sets, Renormalization and MLC Mikhail Lyubich
  234. ON QUASI-INVARIANT CURVES by Ricardo Pérez-Marco
  235. mathoverflow question: fine-structure-of-bifurcation-diagram-of-logistic-family
  236. Near Parabolic Renormalization for Unicritical Holomorphic Maps by Arnaud Chéritat. Arnold Mathematical Journal https://doi.org/10.1007/s40598-020-00172-6
  237. wikipedioa: Surgery theory
  238. Regluing of rational functions by Vladlen Timorin
  239. Tuning From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2014.
  240. Wikipedia: dense set
  241. mathoverflow question: is-there-an-almost-dense-set-of-quadratic-polynomials-which-is-not-in-the-inte/254533#254533
  242. fractalforums: dense-image
  243. A Cheritat wiki: see image showing gamma-correct downscale of dense part of Mandelbropt set
  244. fractal forums: pathfinding-in-the-mandelbrot-set/
  245. quora: Where-is-the-best-summary-on-the-meaning-of-the-terms-elliptic-hyperbolic-parabolic-as-used-in-different-disciplines-in-mathematics
  246. N. Marwan, M. C. Romano, M. Thiel, J. Kurths: Recurrence Plots for the Analysis of Complex Systems, Physics Reports, 438(5-6), 237-329, 2007.
  247. math.stackexchange question: direction-of-x-axis-with-respect-to-y-axis-in-cartesian-coordinate-system
  248. Wikipedia: Conformal radius
  249. scholarpedia: Quadratic Siegel disks
  250. Julia Sets of Complex Polynomials and Their Implementation on the Computer by Christoph Martin Stroh
  251. fractalforums: bounding circle of julia sets by knighty
  252. The Mandelbrot Set and Julia Sets Combinatorics in the Mandelbrot Set - The 1/n2 rule, and deviations from it
  253. Wikipedia: Sequence
  254. Wikipedia: series
  255. Structure of Inverse Limit Spaces of Tent Maps with Nonrecurrent Critical Points by Brian Raines and Sonja Stimac
  256. Bifurcation structures in maps of Henon type by Kai T Hansen and Predrag Cvitanovic
  257. Hausdorff dimension of biaccessible angles of quadratic Julia sets and of the Mandelbrot set by Henk Bruin and Dierk Schleicher
  258. ADMISSIBILITY OF KNEADING SEQUENCES AND STRUCTURE OF HUBBARD TREES FOR QUADRATIC POLYNOMIALS by HENK BRUIN AND DIERK SCHLEICHER
  259. rosetta code: Thue-Morse
  260. Wikipedia: series
  261. quora: Why-is-the-Mandelbrot-set-a-fractal? Answer by Anders Kaseorg
  262. The Existence and Uniqueness of the Taylor Series of Iterated Functions by Daniel Geisler
  263. scholarpedia.org: Attractor
  264. Wikipedia: Continuum in set theory
  265. Harmonic structure of one-dimensional quadratic maps by G. Pastor, M. Romera, and F. Montoya
  266. fractalforums: binary-decomposition-and-external-angles by Claude
  267. Alicia Cordero, Fazlollah Soleymani, Juan R. Torregrosa, Stanford Shateyi, "Basins of Attraction for Various Steffensen-Type Methods", Journal of Applied Mathematics, vol. 2014, Article ID 539707, 17 pages, 2014. https://doi.org/10.1155/2014/539707
  268. mu-atom From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2018.  
  269. A priori bounds for some infinitely renormalizable quadratics: II. Decorations by Jeremy Kahn, Mikhail Lyubich
  270. Mu-atom From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2013.
  271. fractalforums.org: how-thick-are-the-filaments
  272. Island Mu-Molecule by Robert P. Munafo, 2012 Aug 18.
  273. Internal addresses in the Mandelbrot set and Galois groups of polynomials by Dierk Schleicher, page 31
  274. notes by Lyubich
  275. Satellite copies of the Mandelbrot set by Luna Lomonaco
  276. mathoverflow: precise-location-of-the-mandelbrot-bulb-attachment-to-the-main-cardioid
  277. ON BIACCESSIBLE POINTS OF THE MANDELBROT SET by SAEED ZAKERI
  278. Child From the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2013.
  279. Surgery in Complex Dynamics by Carsten Lunde Petersen, online paper
  280. Internal addresses in the Mandelbrot set and irreducibility of polynomials by Dierk Schleicher
  281. Dynamics of quadratic polynomials, I: Combinatorics and geometry of the Yoccoz puzzle by Mikhail Lyubich
  282. Gary William Flake, The Computational Beauty of Nature, 1998. p. 125. ISBN 978-0-262-56127-3.
  283. Dynamics of quadratic polynomials, I: Combinatorics and geometry of the Yoccoz puzzle by Mikhail Lyubich
  284. Counting Hyperbolic Components in the Main Molecule by Schinella D'Souza
  285. the Mandelbrot Set Glossary and Encyclopedia, by Robert Munafo, (c) 1987-2018
  286. Romera, Miguel & Pastor, Gerardo & Alvarez, Gonzalo & Vitini, Fausto. (2003). Shrubs in the Mandelbrot Set Ordering. International Journal of Bifurcation and Chaos. 13. 10.1142/S0218127403007941.
  287. Local properties of the Mandelbrot set at parabolic points by Tan Lei
  288. wikipedia: Classification_of_Fatou_components
  289. math.stackexchange question: quasiconformal-automorphism-groups-of-julia-sets
  290. Wikipedia: Carathéodory's theorem (conformal mapping)
  291. The intrinsic geometry of a Jordan domain by Richard L. Bishop
  292. math.stackexchange question: definition-of-markov-partition
  293. Norman Lebovitz: Textbook for Mathematics 27300
  294. On the Measure of the Feigenbaum Julia Set Scott Sutherland Stony Brook University Joint work with Artem Dudko, IMPAN Bedlewo, Poland 22 March 2018
  295. Wikipedia: Level set
  296. Weisstein, Eric W. "Pear Curve." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/PearCurve.html
  297. Mandelbrot lemniscate at 2DCurves by Jan Wassenaar
  298. Polynomial_lemniscate
  299. Limits of Polynomial-like Quadratic Rational Maps III: The Cantor Locus by Eva Uhre
  300. A. Blokh, X. Buff, A. Cheritat, L. Oversteegen The solar Julia sets of basic quadratic Cremer polynomials, Ergodic Theory and Dynamical Systems, 30 (2010), #1, 51-65
  301. Prescribing the Postsingular Dynamics of Meromorphic Functions by Christopher J. Bishop, Kirill Lazebnik
  302. Dynamics of complex unicritical polynomials. A Dissertation Presented by Davoud Cheraghi
  303. On the postcritical set of a rational map by Laura G. DeMarco, Sarah C. Koch and Curtis T. McMullen
  304. Dynamics of hyperbolic correspondences by Carlos Siqueira
  305. Hyperoperations Wiki: Shell-Thron_region
  306. Prescribing the Postsingular Dynamics of Meromorphic Functions by Christopher J. Bishop, Kirill Lazebnik
  307. Fractus doc by Richard Rosenman
  308. Wikipedia: Escaping set
  309. fractint doc: bailout
  310. A landing theorem for entire functions with bounded post-singular sets by Anna Miriam Benini, Lasse Rempe-Gillen