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arXiv · 2210.08515

Klyachko diagrams of monomial ideals

Rosa M. Miró-Roig·Martí Salat-Moltó
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Abstract

In this paper, we introduce the notion of a Klyachko diagram for a monomial ideal $I$ in a certain multi-graded polynomial ring, namely the Cox ring $R$ of a smooth complete toric variety, with irrelevant maximal ideal $B$. We present procedures to compute the Klyachko diagram of $I$ from its monomial generators, and to retrieve the $B-$saturation $I^{\mathrm{sat}}$ of $I$ from its Klyachko diagram. We use this description to compute the first local cohomology module $H^{1}_{B}(I)$. As an application, we find a formula for the Hilbert function of $I^{\mathrm{sat}}$, and a characterization of monomial ideals with constant Hilbert polynomial, in terms of their Klyachko diagram.

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Rosa M. Miró-Roig, Martí Salat-Moltó. 2022-10-16. Klyachko diagrams of monomial ideals. https://doi.org/10.1007/s10468-022-10146-1

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