Hook restriction coefficients

Fuente: arXiv
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Auteur principal: Narayanan, Sridhar P.
Format: Preprint
Publié: 2024
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author Narayanan, Sridhar P.
author_facet Narayanan, Sridhar P.
contents The permutation matrices form a subgroup of $\text{GL}_n(\mathbb{C})$ that is isomorphic to the symmetric group $S_n$. Let $r_{μλ}$ denote the multiplicity of the irreducible representation $V_μ$ of $S_n$, corresponding to a partition $μ$ of $n$, in the restriction of an irreducible polynomial representation $W_λ(\mathbb{C})$ of $\text{GL}_n(\mathbb{C})$, corresponding to a partition $λ$ with at most $n$ parts. Finding a combinatorial interpretation for $r_{μλ}$ remains an open problem in algebraic combinatorics, called the \emph{restriction problem}. We derive a new nonrecursive expression for a character polynomial called the \emph{Specht polynomial} and use it to find a combinatorial interpretation of $r_{μλ}$ when $λ$ is a hook-shaped partition.
format Preprint
id arxiv_https___arxiv_org_abs_2403_03443
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hook restriction coefficients
Narayanan, Sridhar P.
Combinatorics
Representation Theory
05E10 (Primary), 20C15, 20C30 (Secondary)
The permutation matrices form a subgroup of $\text{GL}_n(\mathbb{C})$ that is isomorphic to the symmetric group $S_n$. Let $r_{μλ}$ denote the multiplicity of the irreducible representation $V_μ$ of $S_n$, corresponding to a partition $μ$ of $n$, in the restriction of an irreducible polynomial representation $W_λ(\mathbb{C})$ of $\text{GL}_n(\mathbb{C})$, corresponding to a partition $λ$ with at most $n$ parts. Finding a combinatorial interpretation for $r_{μλ}$ remains an open problem in algebraic combinatorics, called the \emph{restriction problem}. We derive a new nonrecursive expression for a character polynomial called the \emph{Specht polynomial} and use it to find a combinatorial interpretation of $r_{μλ}$ when $λ$ is a hook-shaped partition.
title Hook restriction coefficients
topic Combinatorics
Representation Theory
05E10 (Primary), 20C15, 20C30 (Secondary)
url https://arxiv.org/abs/2403.03443