Download or read book Hqfts and Quantum Groups written by Neha Gupta and published by LAP Lambert Academic Publishing. This book was released on 2012 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis is divided into two parts one for dimension 2 and the other for dimension 3. Part one of the thesis generalizes the de nition of an n-dimensional HQFT in terms of a monoidal functor from a rigid symmetric monoidal category X Cobn to any monoidal category A. In particular, 2-dimensional HQFTs with target K(G,1) taking values in A are generated from any Turaev G-crossed system in A and vice-versa. This is the generalization of Turaev's theory into a purely categorical set-up. Part two of the thesis generalizes the concept of a group-coalgebra, Hopf group-coalgebra, crossed Hopf group-coalgebra and quasitriangular Hopf group-coalgebra over a group scheme. Quantum double of a crossed Hopf group-scheme coalgebra is constructed in the a ne case and conjectured for non-a ne case. We can construct 3-dimensional HQFTs from modular crossed G-categories. The category of representations of a quantum double of a crossed Hopf group-coalgebra is a ribbon(quasitriangular) crossed group-category. Hence generates 3-dimensional HQFTs under certain conditions if the category becomes modular. However, systematic nding of modular crossed G-categories is largely open."