English

Reconstruction of tensor categories from their structure invariants

Category Theory 2018-02-06 v1 Rings and Algebras

Abstract

In this paper, we study tensor (or monoidal) categories of finite rank over an algebraically closed field F\mathbb F. Given a tensor category C\mathcal{C}, we have two structure invariants of C\mathcal{C}: the Green ring (or the representation ring) r(C)r(\mathcal{C}) and the Auslander algebra A(C)A(\mathcal{C}) of C\mathcal{C}. We show that a Krull-Schmit abelian tensor category C\mathcal{C} of finite rank is uniquely determined (up to tensor equivalences) by its two structure invariants and the associated associator system of C\mathcal{C}. In fact, we can reconstruct the tensor category C\mathcal{C} from its two invarinats and the associator system. More general, given a quadruple (R,A,ϕ,a)(R, A, \phi, a) satisfying certain conditions, where RR is a Z+\mathbb{Z}_+-ring of rank nn, AA is a finite dimensional F\mathbb F-algebra with a complete set of nn primitive orthogonal idempotents, ϕ\phi is an algebra map from AFAA\otimes_{\mathbb F}A to an algebra M(R,A,n)M(R, A, n) constructed from AA and RR, and a={ai,j,l1<i,j,l<n}a=\{a_{i,j,l}|1< i,j,l<n\} is a family of "invertible" matrices over AA, we can construct a Krull-Schmidt and abelian tensor category C\mathcal C over F\mathbb{F} such that RR is the Green ring of C\mathcal C and AA is the Auslander algebra of C\mathcal C. In this case, C\mathcal C has finitely many indecomposable objects (up to isomorphisms) and finite dimensional Hom-spaces. Moreover, we will give a necessary and sufficient condition for such two tensor categories to be tensor equivalent.

Keywords

Cite

@article{arxiv.1802.00969,
  title  = {Reconstruction of tensor categories from their structure invariants},
  author = {Huixiang Chen and Yinhuo Zhang},
  journal= {arXiv preprint arXiv:1802.00969},
  year   = {2018}
}
R2 v1 2026-06-23T00:09:40.040Z