English

Twisted separability for adjoint functors

Category Theory 2023-07-13 v1 Quantum Algebra

Abstract

Twisted separable functors generalize the separable functors of Nastasescu, Van den Bergh and Van Oystaeyen, and provide a convenient tool to compare various projective dimensions. We discuss when an adjoint functor is twisted separable, obtaining a version of Rafael's Theorem in the twisted case. As an application, we show that if RR is Hopf-Galois object over a Hopf algebra AA, then their Hochschild cohomological dimension coincide, provided that the cohomological dimension of AA is finite and that RR has a unital twisted trace with respect to a semi-colinear automorphism.

Keywords

Cite

@article{arxiv.2307.05980,
  title  = {Twisted separability for adjoint functors},
  author = {Julien Bichon},
  journal= {arXiv preprint arXiv:2307.05980},
  year   = {2023}
}