An equivalence between Frobenius algebras and Calabi-Yau categories

Abstract

We show that the bigroupoid of separable symmetric Frobenius algebras over an algebraically closed field and the bigroupoid of finitely semi-simple Calabi-Yau categories are equivalent. To this end, we construct a trace on the category of finitely-generated representations of a symmetric, separable Frobenius algebra, given by the composite of the Frobenius form with the Hattori-Stallings trace. In order to put this result into perspective, we introduce the concept of the equivariantization of a 2-functor between bicategories endowed with a G-action. We prove that the equivalence between Frobenius algebras and Calabi-Yau categories is actually the equivariantization of the 2-functor sending a separable algebra to its category of finitely-generated modules, where we endow both the bicategory of algebras, bimodules and intertwiners and the bicategory of linear categories with the trivial SO(2)-action and take homotopy fixed points as considered in [HSV16].

Published in J. Homotopy Relat. Struct. with an appendix on equivariant 2-functors