On Laplacian and Signless Laplacian Permanental Polynomials of Some Well-known Graphs

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Hauptverfasser: Mitra, Sarbari, Bhoumik, Soumya
Format: Preprint
Veröffentlicht: 2025
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author Mitra, Sarbari
Bhoumik, Soumya
author_facet Mitra, Sarbari
Bhoumik, Soumya
contents The permanent of an $n \times n$ matrix $M = (m_{ij})$ is defined as $\mathrm{per}(M) = \sum_{σ\in S_n} \prod_{i=1}^n m_{i,σ(i)}$, where $S_n$ denotes the symmetric group on $\{1,2,\ldots,n\}$. The permanental polynomial of $M$, is defined by $ψ(M;x) = \mathrm{per}(xI_n - M)$. We study two fundamental variants: the Laplacian permanental polynomial $ψ(L(G);x)$ and signless Laplacian permanental polynomial $ψ(Q(G);x)$ of a graph $G$. A graph is said to be {determined} by its (signless) Laplacian permanental polynomial if no other non-isomorphic graph shares the same polynomial. A graph is combinedly determined when isomorphism is guaranteed by the equality of both polynomials. Characterizing which graphs are determined by their(signless) Laplacian permanental polynomials is an interesting problem. This paper investigates the permanental characterization problem for several families of starlike graphs, including: spider graphs (tree), coconut tree, perfect binary tree, corona product of $C_m$ and $K_n$, and $\bar K_n$ for various values of $m$ and $n$. We establish which of these graphs are determined by their Laplacian or signless Laplacian permanental polynomials, and which require both polynomials for complete characterization. We emphasize that in this manuscript, we have considered a few techniques to compute the permanental polynomial of matrices and their propagation.
format Preprint
id arxiv_https___arxiv_org_abs_2509_14389
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On Laplacian and Signless Laplacian Permanental Polynomials of Some Well-known Graphs
Mitra, Sarbari
Bhoumik, Soumya
Combinatorics
05C31, 05C50, 15A15, 05C60
The permanent of an $n \times n$ matrix $M = (m_{ij})$ is defined as $\mathrm{per}(M) = \sum_{σ\in S_n} \prod_{i=1}^n m_{i,σ(i)}$, where $S_n$ denotes the symmetric group on $\{1,2,\ldots,n\}$. The permanental polynomial of $M$, is defined by $ψ(M;x) = \mathrm{per}(xI_n - M)$. We study two fundamental variants: the Laplacian permanental polynomial $ψ(L(G);x)$ and signless Laplacian permanental polynomial $ψ(Q(G);x)$ of a graph $G$. A graph is said to be {determined} by its (signless) Laplacian permanental polynomial if no other non-isomorphic graph shares the same polynomial. A graph is combinedly determined when isomorphism is guaranteed by the equality of both polynomials. Characterizing which graphs are determined by their(signless) Laplacian permanental polynomials is an interesting problem. This paper investigates the permanental characterization problem for several families of starlike graphs, including: spider graphs (tree), coconut tree, perfect binary tree, corona product of $C_m$ and $K_n$, and $\bar K_n$ for various values of $m$ and $n$. We establish which of these graphs are determined by their Laplacian or signless Laplacian permanental polynomials, and which require both polynomials for complete characterization. We emphasize that in this manuscript, we have considered a few techniques to compute the permanental polynomial of matrices and their propagation.
title On Laplacian and Signless Laplacian Permanental Polynomials of Some Well-known Graphs
topic Combinatorics
05C31, 05C50, 15A15, 05C60
url https://arxiv.org/abs/2509.14389