Fundamental group of Schurian categories and the Hurewicz isomorphism

Abstract

Let k be a field. We attach a CW-complex to any Schurian k-category and we prove that the fundamental group of this CW-complex is isomorphic to the intrinsic fundamental group of the k-category. This extends previous results by J.C. Bustamante in [8]. We also prove that the Hurewicz morphism from the vector space of abelian characters of the fundamental group to the first Hochschild-Mitchell cohomology vector space of the category is an isomorphism. 2010 MSC: 55Q05 18D20 16E40 16W25 16W50