On invariants of representations of Weyl groups associated with the cohomology of toric varieties

Fuente: arXiv
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Main Author: Gong, Tao
Format: Preprint
Published: 2026
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author Gong, Tao
author_facet Gong, Tao
contents For a Weyl group $W$ and a $W$-permutohedron $P$, there are associated toric varieties $X_P$ and $X_{P/W_K}$ for any parabolic subgroup $W_K$ of $W$, since the quotient $P/W_K$ can be identified with a polytope inside $P$. We construct an explicit algebra isomorphism between $H^*(X_{P/W_K};\mathbb{Q})$ and $H^*(X_P;\mathbb{Q})^{W_K}$. We further generalize this isomorphism to intermediate lattices, to finite Coxeter groups, and to non-degenerate $W$-symmetric polytopes. Our results give affirmative answers to two open questions of Horiguchi--Masuda--Shareshain--Song.
format Preprint
id arxiv_https___arxiv_org_abs_2602_23631
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle On invariants of representations of Weyl groups associated with the cohomology of toric varieties
Gong, Tao
Algebraic Topology
Algebraic Geometry
Representation Theory
Primary 13A50, Secondary 14M25, 20F55, 52B20
For a Weyl group $W$ and a $W$-permutohedron $P$, there are associated toric varieties $X_P$ and $X_{P/W_K}$ for any parabolic subgroup $W_K$ of $W$, since the quotient $P/W_K$ can be identified with a polytope inside $P$. We construct an explicit algebra isomorphism between $H^*(X_{P/W_K};\mathbb{Q})$ and $H^*(X_P;\mathbb{Q})^{W_K}$. We further generalize this isomorphism to intermediate lattices, to finite Coxeter groups, and to non-degenerate $W$-symmetric polytopes. Our results give affirmative answers to two open questions of Horiguchi--Masuda--Shareshain--Song.
title On invariants of representations of Weyl groups associated with the cohomology of toric varieties
topic Algebraic Topology
Algebraic Geometry
Representation Theory
Primary 13A50, Secondary 14M25, 20F55, 52B20
url https://arxiv.org/abs/2602.23631