Engineering Analysis/Function Spaces

Function Space edit

A function space is a linear space where all the elements of the space are functions. A function space that has a norm operation is known as a normed function space. The spaces we consider will all be normed.

Continuity edit

f(x) is continuous at x0 if, for every ε > 0 there exists a δ(ε) > 0 such that |f(x) - f(x0)| < ε when |x - x0| < δ(ε).

Common Function Spaces edit

Here is a listing of some common function spaces. This is not an exhaustive list.

C Space edit

The C function space is the set of all functions that are continuous.

The metric for C space is defined as:

 

Consider the metric of sin(x) and cos(x):

 

Cp Space edit

The Cp is the set of all continuous functions for which the first p derivatives are also continuous. If   the function is called "infinitely continuous. The set   is the set of all such functions. Some examples of functions that are infinitely continuous are exponentials, sinusoids, and polynomials.

L Space edit

The L space is the set of all functions that are finitely integrable over a given interval [a, b].

f(x) is in L(a, b) if:

 

L p Space edit

The Lp space is the set of all functions that are finitely integrable over a given interval [a, b] when raised to the power p:

 

Most importantly for engineering is the L2 space, or the set of functions that are "square integrable".