Depth and Regularity of Monomial Ideals via Polarization and Combinatorial Optimization

In this paper, we use polarization to study the behavior of the depth and regularity of a monomial ideal I , locally at a variable x i , when we lower the degree of all the highest powers of the variable x i occurring in the minimal generating set of I , and examine the depth and regularity of power...

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Bibliographic Details
Published inActa mathematica vietnamica Vol. 44; no. 1; pp. 243 - 268
Main Authors Martínez-Bernal, José, Morey, Susan, Villarreal, Rafael H., Vivares, Carlos E.
Format Journal Article
LanguageEnglish
Published Singapore Springer Singapore 15.03.2019
Springer Nature B.V
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Summary:In this paper, we use polarization to study the behavior of the depth and regularity of a monomial ideal I , locally at a variable x i , when we lower the degree of all the highest powers of the variable x i occurring in the minimal generating set of I , and examine the depth and regularity of powers of edge ideals of clutters using combinatorial optimization techniques. If I is the edge ideal of an unmixed clutter with the max-flow min-cut property, we show that the powers of I have non-increasing depth and non-decreasing regularity. In particular, edge ideals of unmixed bipartite graphs have non-decreasing regularity. We are able to show that the symbolic powers of the ideal of covers of the clique clutter of a strongly perfect graph have non-increasing depth. A similar result holds for the ideal of covers of a uniform ideal clutter.
ISSN:0251-4184
2315-4144
DOI:10.1007/s40306-018-00308-z