English

Betti numbers of graded modules and the Multiplicity Conjecture in the non-Cohen-Macaulay case

Commutative Algebra 2008-03-12 v1 Algebraic Geometry

Abstract

We use the results by Eisenbud and Schreyer to prove that any Betti diagram of a graded module over a standard graded polynomial ring is a positive linear combination Betti diagrams of modules with a pure resolution. This implies the Multiplicity Conjecture of Herzog, Huneke and Srinivasan for modules that are not necessarily Cohen-Macaulay. We give a combinatorial proof of the convexity of the simplicial fan spanned by the pure diagrams.

Keywords

Cite

@article{arxiv.0803.1645,
  title  = {Betti numbers of graded modules and the Multiplicity Conjecture in the non-Cohen-Macaulay case},
  author = {Mats Boij and Jonas Soderberg},
  journal= {arXiv preprint arXiv:0803.1645},
  year   = {2008}
}

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14 pages