The poset of proper divisibility

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2017

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Mcode

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Language

en

Pages

17
2093-2109

Series

SIAM Journal on Discrete Mathematics, Volume 31, issue 3

Abstract

We study the partially ordered set P(a1, ... , an) of all multidegrees (b1, ... , bn) of monomials xb1 1 ... xbn n, which properly divide xa1 1 ... xan n . We prove that the order complex Δ(P(a1, ... , an)) of P(a1, ... an) is (nonpure) shellable by showing that the order dual of P(a1, ... , an) is CL-shellable. Along the way, we exhibit the poset P(4, 4) as a new example of a poset with CL-shellable order dual that is not CL-shellable itself. For n = 2, we provide the rank of all homology groups of the order complex δ(P(a1, a2)). Furthermore, we give a succinct formula for the Euler characteristic of δ(P(a1, a2)).

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Keywords

CL-shellability, Euler characteristic, Posets, Proper division, Simplicial homology

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Citation

Bolognini , D , Macchia , A , Ventura , E & Welker , V 2017 , ' The poset of proper divisibility ' , SIAM Journal on Discrete Mathematics , vol. 31 , no. 3 , pp. 2093-2109 . https://doi.org/10.1137/15M1049142