Limbs and Cospectral Vertices in Trees

Fuente: arXiv
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Autores principales: Wang, Caelan, Yeats, Karen
Formato: Preprint
Publicado: 2018
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author Wang, Caelan
Yeats, Karen
author_facet Wang, Caelan
Yeats, Karen
contents We generalize Schwenk's result that almost all trees contain any given limb to trees with positive integer vertex weights. The concept of characteristic polynomial is extended to such weighted trees and we prove that the proportion of $n$-vertex weighted trees that is weighted cospectral to another $n$-vertex weighted tree approaches $1$ as $n$ approaches infinity. We also prove that, for any integer $k\ge 2$, the proportion of $n$-vertex trees containing $k$ non-similar cospectral vertices approaches $1$ as $n$ approaches infinity.
format Preprint
id arxiv_https___arxiv_org_abs_1811_12344
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle Limbs and Cospectral Vertices in Trees
Wang, Caelan
Yeats, Karen
Combinatorics
We generalize Schwenk's result that almost all trees contain any given limb to trees with positive integer vertex weights. The concept of characteristic polynomial is extended to such weighted trees and we prove that the proportion of $n$-vertex weighted trees that is weighted cospectral to another $n$-vertex weighted tree approaches $1$ as $n$ approaches infinity. We also prove that, for any integer $k\ge 2$, the proportion of $n$-vertex trees containing $k$ non-similar cospectral vertices approaches $1$ as $n$ approaches infinity.
title Limbs and Cospectral Vertices in Trees
topic Combinatorics
url https://arxiv.org/abs/1811.12344