On a Bruhat decomposition related to the Shalika subgroup of $GL(2n)$

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Main Authors: Harshitha, C., Venketasubramanian, C. G.
Format: Preprint
Published: 2025
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author Harshitha, C.
Venketasubramanian, C. G.
author_facet Harshitha, C.
Venketasubramanian, C. G.
contents Let $F$ be a non-archimedean local field or a finite field. In this article, we obtain an explicit and complete set of double coset representatives for $S\backslash GL_{2n}(F)/Q$ where $S$ is the Shalika subgroup and $Q$ a maximal parabolic subgroup of the group $GL_{2n}(F)$ of invertible $2n\times 2n$ matrices. We compute the cardinality of $S\backslash GL_{2n}(F)/Q$ and also give an alternate perspective on the double cosets arising intrinsically from certain subgroups which are relevant for applications in representation theory. Finally, if $Q$ is a maximal parabolic subgroup of the type $(r,2n-r),$ we prove that $S\backslash GL_{2n}(F)/Q$ is in one to one correspondence with $ΔS_n\backslash S_{2n}/S_{r}\times S_{2n-r}$ leading to a Bruhat decomposition. The results and proofs discussed in this article are valid over any arbitrary field $F$ even though our motivation is from representation theory of $p$-adic and finite linear groups.
format Preprint
id arxiv_https___arxiv_org_abs_2512_24368
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On a Bruhat decomposition related to the Shalika subgroup of $GL(2n)$
Harshitha, C.
Venketasubramanian, C. G.
Representation Theory
Group Theory
20G05, 22E50
Let $F$ be a non-archimedean local field or a finite field. In this article, we obtain an explicit and complete set of double coset representatives for $S\backslash GL_{2n}(F)/Q$ where $S$ is the Shalika subgroup and $Q$ a maximal parabolic subgroup of the group $GL_{2n}(F)$ of invertible $2n\times 2n$ matrices. We compute the cardinality of $S\backslash GL_{2n}(F)/Q$ and also give an alternate perspective on the double cosets arising intrinsically from certain subgroups which are relevant for applications in representation theory. Finally, if $Q$ is a maximal parabolic subgroup of the type $(r,2n-r),$ we prove that $S\backslash GL_{2n}(F)/Q$ is in one to one correspondence with $ΔS_n\backslash S_{2n}/S_{r}\times S_{2n-r}$ leading to a Bruhat decomposition. The results and proofs discussed in this article are valid over any arbitrary field $F$ even though our motivation is from representation theory of $p$-adic and finite linear groups.
title On a Bruhat decomposition related to the Shalika subgroup of $GL(2n)$
topic Representation Theory
Group Theory
20G05, 22E50
url https://arxiv.org/abs/2512.24368