The identification of an optimized model is one of the key issues in the field of fuzzy system modeling. This has gained significant importance since; most of the real life systems are highly complex and nonlinear. Fuzzy model identification involves two stages i.e. identification of input and output membership functions as well as generation of rule base for the system being modeled. The fuzzy...

We study a quotient Conformal Field Theory, which describes a 3 + 1 dimensional cosmological spacetime. Part of this spacetime is the Nappi-Witten (NW) universe, which starts at a “big bang” singularity, expands and then contracts to a “big crunch” singularity at a finite time. The gauged WZW model contains a number of copies of the NW spacetime, with each copy connected to the preceeding one a...

We consider spacetimes N satisfying some structural conditions, which are still fairly general, and prove convergence results for the leaves of an inverse mean curvature flow. Moreover, we define a new spacetime N̂ by switching the light cone and using reflection to define a new time function, such that the two spacetimes N and N̂ can be pasted together to yield a smooth manifold having a metric ...