English

Betti numbers of Stanley--Reisner rings with pure resolutions

Commutative Algebra 2011-02-01 v2 Combinatorics

Abstract

Let Δ\Delta be simplicial complex and let k[Δ]k[\Delta] denote the Stanley--Reisner ring corresponding to Δ\Delta. Suppose that k[Δ]k[\Delta] has a pure free resolution. Then we describe the Betti numbers and the Hilbert--Samuel multiplicity of k[Δ]k[\Delta] in terms of the hh--vector of Δ\Delta. As an application, we derive a linear equation system for the components of the hh--vector of the clique complex of an arbitrary chordal graph.

Keywords

Cite

@article{arxiv.1101.5565,
  title  = {Betti numbers of Stanley--Reisner rings with pure resolutions},
  author = {Gabor Hegedüs},
  journal= {arXiv preprint arXiv:1101.5565},
  year   = {2011}
}

Comments

10 pages, new formulas for the components of the clique complex of chordal graphs