English

Homological degrees of representations of categories with shift functors

Representation Theory 2015-10-23 v3 K-Theory and Homology Rings and Algebras

Abstract

Let kk be a commutative Noetherian ring and C\underline{\mathscr{C}} be a locally finite kk-linear category equipped with a self-embedding functor of degree 1. We show under a moderate condition that finitely generated torsion representations of C\underline{\mathscr{C}} are super finitely presented (that is, they have projective resolutions each term of which is finitely generated). In the situation that these self-embedding functors are genetic functors, we give upper bounds for homological degrees of finitely generated torsion modules. These results apply to quite a few categories recently appearing in representation stability theory. In particular, when kk is a field of characteristic 0, we obtain another upper bound for homological degrees of finitely generated FI\mathrm{FI}-modules.

Keywords

Cite

@article{arxiv.1507.08023,
  title  = {Homological degrees of representations of categories with shift functors},
  author = {Liping Li},
  journal= {arXiv preprint arXiv:1507.08023},
  year   = {2015}
}

Comments

Major changes include: A stronger upper bound for homological degrees of torsion modules; a new proof of the Koszulity of categories with shift functors; a new upper bound for homological degrees of FI-modules, etc