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Autori principali: Josuat-Vergès, Matthieu, Nadeau, Philippe
Natura: Preprint
Pubblicazione: 2021
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Accesso online:https://arxiv.org/abs/2107.13442
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author Josuat-Vergès, Matthieu
Nadeau, Philippe
author_facet Josuat-Vergès, Matthieu
Nadeau, Philippe
contents The dual braid monoid was introduced by Bessis in his work on complex reflection arrangements. The goal of this work is to show that Koszul duality provides a nice interplay between the dual braid monoid and the cluster complex introduced by Fomin and Zelevinsky. Firstly, we prove koszulity of the dual braid monoid algebra, by building explicitly the minimal free resolution of the ground field. This is done explicitly using some chains complexes defined in terms of the positive part of the cluster complex. Secondly, we derive various properties of the quadratic dual algebra. We show that it is naturally graded by the noncrossing partition lattice. We get an explicit basis, naturally indexed by positive faces of the cluster complex. Moreover, we find the structure constants via a geometric rule in terms of the cluster fan. Eventually, we realize this dual algebra as a quotient of a Nichols algebra. This latter fact makes a connection with results of Zhang, who used the same algebra to compute the homology of Milnor fibers of reflection arrangements.
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id arxiv_https___arxiv_org_abs_2107_13442
institution arXiv
publishDate 2021
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spellingShingle Koszulity of dual braid monoid algebras via cluster complexes
Josuat-Vergès, Matthieu
Nadeau, Philippe
Combinatorics
Representation Theory
The dual braid monoid was introduced by Bessis in his work on complex reflection arrangements. The goal of this work is to show that Koszul duality provides a nice interplay between the dual braid monoid and the cluster complex introduced by Fomin and Zelevinsky. Firstly, we prove koszulity of the dual braid monoid algebra, by building explicitly the minimal free resolution of the ground field. This is done explicitly using some chains complexes defined in terms of the positive part of the cluster complex. Secondly, we derive various properties of the quadratic dual algebra. We show that it is naturally graded by the noncrossing partition lattice. We get an explicit basis, naturally indexed by positive faces of the cluster complex. Moreover, we find the structure constants via a geometric rule in terms of the cluster fan. Eventually, we realize this dual algebra as a quotient of a Nichols algebra. This latter fact makes a connection with results of Zhang, who used the same algebra to compute the homology of Milnor fibers of reflection arrangements.
title Koszulity of dual braid monoid algebras via cluster complexes
topic Combinatorics
Representation Theory
url https://arxiv.org/abs/2107.13442