Homological criteria for minimal multiplicity
Abstract
Lower bounds on Hilbert-Samuel multiplicity are known for several types of commutative noetherian local rings, and rings with multiplicities which achieve these lower bounds are said to have minimal multiplicity. The first part of this paper gives characterizations of rings of minimal multiplicity in terms of the Ext-algebra of the ring; in particular, we show that minimal multiplicity can be detected via an Ext-algebra which is Gorenstein or Koszul AS-regular. The second part of this paper characterizes rings of minimal multiplicity via a numerical homological invariant introduced by J. Herzog and S. B. Iyengar called linearity defect. Our characterizations allow us to answer in two special cases a question raised by Herzog and Iyengar.
Keywords
Cite
@article{arxiv.1803.05454,
title = {Homological criteria for minimal multiplicity},
author = {John Myers},
journal= {arXiv preprint arXiv:1803.05454},
year = {2019}
}
Comments
Final version; minor changes made according to the referee report; to appear in the Journal of Algebra