A Short Proof for the Polynomiality of the Stretched Littlewood-Richardson Coefficients

Fuente: arXiv
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Main Author: Thawinrak, Warut
Format: Preprint
Published: 2022
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_version_ 1866909247659311104
author Thawinrak, Warut
author_facet Thawinrak, Warut
contents The stretched Littlewood-Richardson coefficient $c^{tν}_{tλ,tμ}$ was conjectured by King, Tollu, and Toumazet to be a polynomial function in $t.$ It was shown to be true by Derksen and Weyman using semi-invariants of quivers. Later, Rassart used Steinberg's formula, the hive conditions, and the Kostant partition function to show a stronger result that $c^ν_{λ,μ}$ is indeed a polynomial in variables $ν, λ, μ$ provided they lie in certain polyhedral cones. Motivated by Rassart's approach, we give a short alternative proof of the polynomiality of $c^{tν}_{tλ,tμ}$ using Steinberg's formula and a simple argument about the chamber complex of the Kostant partition function.
format Preprint
id arxiv_https___arxiv_org_abs_2211_06810
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle A Short Proof for the Polynomiality of the Stretched Littlewood-Richardson Coefficients
Thawinrak, Warut
Combinatorics
The stretched Littlewood-Richardson coefficient $c^{tν}_{tλ,tμ}$ was conjectured by King, Tollu, and Toumazet to be a polynomial function in $t.$ It was shown to be true by Derksen and Weyman using semi-invariants of quivers. Later, Rassart used Steinberg's formula, the hive conditions, and the Kostant partition function to show a stronger result that $c^ν_{λ,μ}$ is indeed a polynomial in variables $ν, λ, μ$ provided they lie in certain polyhedral cones. Motivated by Rassart's approach, we give a short alternative proof of the polynomiality of $c^{tν}_{tλ,tμ}$ using Steinberg's formula and a simple argument about the chamber complex of the Kostant partition function.
title A Short Proof for the Polynomiality of the Stretched Littlewood-Richardson Coefficients
topic Combinatorics
url https://arxiv.org/abs/2211.06810