KW Semigroups -- Their Betti Numbers, Apéry Posets and Tangent Cones

Mario González-Sánchez; Hema Srinivasan

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arXiv · 2605.27035

KW Semigroups -- Their Betti Numbers, Apéry Posets and Tangent Cones

Mario González-Sánchez·Hema Srinivasan

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Abstract

Let p , where 2r=p,q,p+q whichever is even. In this paper, we prove a conjecture on the Betti numbers of the semigroup rings of these semigroups, showing that they coincide with those of the ideal of 2x2 minors of a 2xn generic matrix, where n is the embedding dimension. Moreover, we characterize the Apéry posets of Kunz-Waldi semigroups and determine when their tangent cones are Cohen-Macaulay.

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Mario González-Sánchez, Hema Srinivasan. 2026-05-26. KW Semigroups -- Their Betti Numbers, Apéry Posets and Tangent Cones. https://arxiv.org/abs/2605.27035

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