Supersymmetry reference removed
Originally the article claimed that the Calabi-Yau condition on the extra dimensions in string theory gave rise to supersymmetry. This claim is in error. Supersymmetric field theories can be defined with or without the Calabi-Yau condition on the extra dimensions. The Calabi-Yau condition is necessary to preserve a different type of symmetry called "conformal invariance".
Incidentally, I am highly skeptical of the article's implication that Greene's main contribution to string theory was to impose the Calabi-Yau condition. My impression is that he's famous for demonstrating an equivalence between two different types of string theory (Type IIA and IIB) when the "extra dimensions" form the shape of a Calabi-Yau quintic. --Lemonpeel 01:15, 16 June 2009 (EDT)