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arXiv · 1601.02793

Resolutions of co-letterplace ideals and generalizations of Bier spheres

Alessio D'Alì·Gunnar Fløystad·Amin Nematbakhsh
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Abstract

We give the resolutions of co-letterplace ideals of posets in a completely explicit, very simple form. This generalizes and simplifies a number of linear resolutions in the literature, among them the Eliahou-Kervaire resolutions of strongly stable ideals generated in a single degree. Our method is based on a general result of K. Yanagawa using the canonical module of a Cohen-Macaulay Stanley-Reisner ring. We discuss in detail how the canonical module may effectively be computed, and from this derive directly the resolutions. A surprising consequence is that we obtain a large class of simplicial spheres comprehensively generalizing Bier spheres.

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Alessio D'Alì, Gunnar Fløystad, Amin Nematbakhsh. 2016-01-12. Resolutions of co-letterplace ideals and generalizations of Bier spheres. https://doi.org/10.1090/tran/7560

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