Action of Hecke algebra on the double flag variety of type AIII

Fuente: arXiv
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Main Authors: Fresse, Lucas, Nishiyama, Kyo
Format: Preprint
Published: 2022
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author Fresse, Lucas
Nishiyama, Kyo
author_facet Fresse, Lucas
Nishiyama, Kyo
contents Consider a connected reductive algebraic group $ G $ and a symmetric subgroup $ K $. Let $ \mathfrak{X} = K/B_K \times G/P $ be a double flag variety of finite type, where $ B_K $ is a Borel subgroup of $ K $, and $ P $ a parabolic subgroup of $ G $. A general argument shows that the orbit space $ \mathbb{C}\,\mathfrak{X}/K $ inherits a natural action of the Hecke algebra $ \mathscr{H} = \mathscr{H}(K, B_K) $ of double cosets via convolutions. However, to find out the explicit structure of the Hecke module is a quite different problem. In this paper, we determine the explicit action of $ \mathscr{H} $ on $ \mathbb{C}\,\mathfrak{X}/K $ in a combinatorial way using graphs for the double flag variety of type AIII. As a by-product, we also get the description of the representation of the Weyl group on $ \mathbb{C}\,\mathfrak{X}/K $ as a direct sum of induced representations.
format Preprint
id arxiv_https___arxiv_org_abs_2206_10476
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Action of Hecke algebra on the double flag variety of type AIII
Fresse, Lucas
Nishiyama, Kyo
Representation Theory
Primary 20C08, Secondary 14M17, 14M15, 20G05
Consider a connected reductive algebraic group $ G $ and a symmetric subgroup $ K $. Let $ \mathfrak{X} = K/B_K \times G/P $ be a double flag variety of finite type, where $ B_K $ is a Borel subgroup of $ K $, and $ P $ a parabolic subgroup of $ G $. A general argument shows that the orbit space $ \mathbb{C}\,\mathfrak{X}/K $ inherits a natural action of the Hecke algebra $ \mathscr{H} = \mathscr{H}(K, B_K) $ of double cosets via convolutions. However, to find out the explicit structure of the Hecke module is a quite different problem. In this paper, we determine the explicit action of $ \mathscr{H} $ on $ \mathbb{C}\,\mathfrak{X}/K $ in a combinatorial way using graphs for the double flag variety of type AIII. As a by-product, we also get the description of the representation of the Weyl group on $ \mathbb{C}\,\mathfrak{X}/K $ as a direct sum of induced representations.
title Action of Hecke algebra on the double flag variety of type AIII
topic Representation Theory
Primary 20C08, Secondary 14M17, 14M15, 20G05
url https://arxiv.org/abs/2206.10476