
 Supergravity Summary 
  Supergravity models generically result in an unrealistically large cosmological constant in four dimensions, and that constant is difficult to remove, and so require finetuning. 
  Many, if not all supergravity theories are the classical limits of superstring theory (i.e., the limit in which the string is approximated as having zero length, and treated as a dimensionless pointparticle), with the exception of "maximal" 11dimensional supergravity, which is, by definition, a classical limit of Mtheory. 
  IIA SUGRA is the dimensional reductions of 11dimensional supergravity on a circle. 
 www.bookrags.com /Supergravity (5185 words) 
