Hook immanantal equalities for linear combination matrices of (di)graphs and their applications

Fuente: arXiv
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Autores principales: Dong, Xiangshuai, Wu, Tingzeng, Lai, HongJian
Formato: Preprint
Publicado: 2025
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author Dong, Xiangshuai
Wu, Tingzeng
Lai, HongJian
author_facet Dong, Xiangshuai
Wu, Tingzeng
Lai, HongJian
contents Let $χ_λ$ be an irreducible character of the symmetric group $S_n$. For an $n \times n$ matrix $M = (m_{ij})$, define the immanant of $M$ corresponding to $χ_λ$ by \begin{eqnarray*} d_λ(M) = \sum_{σ\in S_n} χ_λ(σ) \prod_{i=1}^n m_{iσ(i)}. \end{eqnarray*} For $λ= (k, 1^{n-k})$, the immanant $d_{(k, 1^{n-k})}(M)$ is called the hook immanant and denoted by $d_k(M)$. The hook immanant polynomial of matrix $M$ is defined as $d_{k}(xI_n - M)$, where $I_n$ is the $n \times n$ identity matrix. Let $G$ and $\overrightarrow{G}$ be a graph and a digraph, respectively. Suppose that $D(G)$ and $A(G)$ (resp. $D(\overrightarrow{G})$ and $A(\overrightarrow{G})$) are the degree matrix and adjacency matrix of $G$ (resp. $\overrightarrow{G}$), respectively. In this paper, we characterize two hook immanantal equalities for the linear combination of matrices $βD(G)+γA(G)$ and $βD(\overrightarrow{G})+γA(\overrightarrow{G})$, where $β$ and $γ$ are real numbers. As applications, we derive recursive formulas for the hook immanantal polynomials and hook immanants of graph matrices.
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id arxiv_https___arxiv_org_abs_2508_17743
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hook immanantal equalities for linear combination matrices of (di)graphs and their applications
Dong, Xiangshuai
Wu, Tingzeng
Lai, HongJian
Combinatorics
Let $χ_λ$ be an irreducible character of the symmetric group $S_n$. For an $n \times n$ matrix $M = (m_{ij})$, define the immanant of $M$ corresponding to $χ_λ$ by \begin{eqnarray*} d_λ(M) = \sum_{σ\in S_n} χ_λ(σ) \prod_{i=1}^n m_{iσ(i)}. \end{eqnarray*} For $λ= (k, 1^{n-k})$, the immanant $d_{(k, 1^{n-k})}(M)$ is called the hook immanant and denoted by $d_k(M)$. The hook immanant polynomial of matrix $M$ is defined as $d_{k}(xI_n - M)$, where $I_n$ is the $n \times n$ identity matrix. Let $G$ and $\overrightarrow{G}$ be a graph and a digraph, respectively. Suppose that $D(G)$ and $A(G)$ (resp. $D(\overrightarrow{G})$ and $A(\overrightarrow{G})$) are the degree matrix and adjacency matrix of $G$ (resp. $\overrightarrow{G}$), respectively. In this paper, we characterize two hook immanantal equalities for the linear combination of matrices $βD(G)+γA(G)$ and $βD(\overrightarrow{G})+γA(\overrightarrow{G})$, where $β$ and $γ$ are real numbers. As applications, we derive recursive formulas for the hook immanantal polynomials and hook immanants of graph matrices.
title Hook immanantal equalities for linear combination matrices of (di)graphs and their applications
topic Combinatorics
url https://arxiv.org/abs/2508.17743