Contents edit

Notation edit

The metric has signature  .

Greek letters from the middle of the alphabet   denote coordinates in spacetime. Roman letters taken from the beginning of the alphabet   denote coordinates on the worldsheet.

The metric is denoted  . In the case where there is a metric of spacetime and a metric of the worldsheet, the worldsheet metric is denoted  

A lower-case   is the number of dimensions. An upper-class   represents the number of spacial dimensions.

The Free String edit

The Bosonic String Theory edit

The Super string theory edit

The Heterotic String Theories edit

String Interactions edit

String Field Theory edit

Compactification edit

Orbifolds and Orientifolds edit

T-Duality edit

D-branes edit

M-Theory edit