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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Published in | Acta mathematica vietnamica Vol. 44; no. 1; pp. 243 - 268 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Singapore
Springer Singapore
15.03.2019
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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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. |
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ISSN: | 0251-4184 2315-4144 |
DOI: | 10.1007/s40306-018-00308-z |