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Autores principales: Kwon, Young Soo, Mednykh, Alexander, Mednykh, Ilya
Formato: Preprint
Publicado: 2021
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Acceso en línea:https://arxiv.org/abs/2111.04297
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author Kwon, Young Soo
Mednykh, Alexander
Mednykh, Ilya
author_facet Kwon, Young Soo
Mednykh, Alexander
Mednykh, Ilya
contents In this paper, we describe the structure of the Laplace characteristic polynomial $χ_n(λ)$ for the infinite family of graphs $H_n=H_n(G_1,\,G_2,\ldots,G_m)$ obtained as a circulant foliation over a graph $H$ on $m$ vertices with fibers $G_1,\,G_2,\ldots,G_m.$ Each fiber $G_i=C_n(s_{i,1},\,s_{i,2},\ldots,s_{i,k_i})$ of this foliation is the circulant graph on $n$ vertices with jumps $s_{i,1},\,s_{i,2},\ldots,s_{i,k_i}.$ This family includes the family of generalized Petersen graphs, $I$-graphs, sandwiches of circulant graphs, discrete torus graphs and others. We show that the characteristic polynomial for such graphs can be decomposed into a finite product of algebraic functions evaluated at the roots of a linear combination of Chebyshev polynomials. Also, we prove that the characteristic polynomial can be represented in the form $χ_n(λ)=p(λ)\,χ_H(λ)a(n)^2,$ where $a(n)$ is a sequence of integer polynomials and $p(λ)$ is a prescribed integer polynomial. Moreover, we use the obtained results to produce analytic formulas for spectral graph invariants, such as the number of spanning trees and the number of spanning rooted forests.
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id arxiv_https___arxiv_org_abs_2111_04297
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle On the structure of Laplace characteristic polynomial for circulant foliation
Kwon, Young Soo
Mednykh, Alexander
Mednykh, Ilya
Combinatorics
05C30, 39A10
In this paper, we describe the structure of the Laplace characteristic polynomial $χ_n(λ)$ for the infinite family of graphs $H_n=H_n(G_1,\,G_2,\ldots,G_m)$ obtained as a circulant foliation over a graph $H$ on $m$ vertices with fibers $G_1,\,G_2,\ldots,G_m.$ Each fiber $G_i=C_n(s_{i,1},\,s_{i,2},\ldots,s_{i,k_i})$ of this foliation is the circulant graph on $n$ vertices with jumps $s_{i,1},\,s_{i,2},\ldots,s_{i,k_i}.$ This family includes the family of generalized Petersen graphs, $I$-graphs, sandwiches of circulant graphs, discrete torus graphs and others. We show that the characteristic polynomial for such graphs can be decomposed into a finite product of algebraic functions evaluated at the roots of a linear combination of Chebyshev polynomials. Also, we prove that the characteristic polynomial can be represented in the form $χ_n(λ)=p(λ)\,χ_H(λ)a(n)^2,$ where $a(n)$ is a sequence of integer polynomials and $p(λ)$ is a prescribed integer polynomial. Moreover, we use the obtained results to produce analytic formulas for spectral graph invariants, such as the number of spanning trees and the number of spanning rooted forests.
title On the structure of Laplace characteristic polynomial for circulant foliation
topic Combinatorics
05C30, 39A10
url https://arxiv.org/abs/2111.04297