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[[../Introduction|Introduction]] [[../Supersymmetry|Supersymmetry]] [[../Two-Dimensional Conformal Field Theory|Two-Dimensional Conformal Field Theory]] [[../String Quantization|String Quantization]] The Free String|The Free String String Interactions String Field Theory Compactification Orbifolds and Orientifolds T-Duality D-branes M-Theory
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.