MTheory 2010-04-07 19:08:19 2010-04-07 19:08:19 Definition a theory of everything atheory o f twodimensional strings = membranes or branes \section{M-theory} is a relatively recently proposed as a theory of everything, including the time evolution through the Big-Bang event that created our universe. It replaces the older string theory in 10 dimensions with a \emph{brane} theory in 11 dimensions, one time dimension and 10 spatial dimensions.