Towards an Algebraic Characterization of 3-dimensional Cobordisms

The goal of this paper is to find a close to isomorphic presentation of 3-manifolds in terms of Hopf algebraic expressions. To this end we define and compare three different braided tensor categories that arise naturally in the study of Hopf algebras and 3-dimensional topology. The first is the category \Cob of connected surfaces with one boundary component and 3-dimensional relative cobordisms, the second is a category \Tgl of tangles with relations, and the third is a natural algebraic category \Alg freely generated by a Hopf algebra object. From previous work we know that {\Tgl} and \Cob are equivalent. We use this fact and the idea of Heegaard splittings to construct a surjective functor from \Alg onto {\Cob}. We also find a map that associates to the generators of the mapping class group in \Cob preimages in \Alg. The single block relations in the mapping class group are verified for these expressions. We propose to find a version of \Alg with possibly additional relations to obatin isomorphic algebraic presentations of the mapping class groups and eventually of \Cob.