Basic Superstring Theory Concepts
string's spacetime history is described by the functions Xm(s,t),
which map the string's two-dimensional world sheet coordinates (s,t)
into the spacetime coordinates Xm.
string theory dynamics is described by a two-dimensional quantum
is the fundamental string scale which is about 10-32 centimeters.
It is also the expansion parameter of this two-dimensional worldsheet
theory. Fortunately, this two-dimensional quantum
theory is renormalizable.