Sets of vertices with extremal energy

Fuente: arXiv
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Main Authors: Bushaw, Neal, Cody, Brent, Leffler, Chris
Format: Preprint
Published: 2024
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author Bushaw, Neal
Cody, Brent
Leffler, Chris
author_facet Bushaw, Neal
Cody, Brent
Leffler, Chris
contents We define various notions of energy of a set of vertices in a graph, which generalize two of the most widely studied graphical indices: the Wiener index and the Harary index. We provide a new proof of a result due to Douthett and Krantz, which says that for cycles, the sets of vertices which have minimal energy among all sets of the same size are precisely the maximally even sets, as defined in Clough and Douthett's work on music theory. Generalizing a theorem of Clough and Douthett, we prove that a finite, simple, connected graph is distance degree regular if and only if whenever a set of vertices has minimal energy, its complement also has minimal energy. We also provide several characterizations of sets of vertices in finite paths and cycles for which the sum of all pairwise distances between vertices in the set is maximal among all sets of the same size.
format Preprint
id arxiv_https___arxiv_org_abs_2407_18785
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Sets of vertices with extremal energy
Bushaw, Neal
Cody, Brent
Leffler, Chris
Combinatorics
05C09, 05C12, 05C35, 05C69
We define various notions of energy of a set of vertices in a graph, which generalize two of the most widely studied graphical indices: the Wiener index and the Harary index. We provide a new proof of a result due to Douthett and Krantz, which says that for cycles, the sets of vertices which have minimal energy among all sets of the same size are precisely the maximally even sets, as defined in Clough and Douthett's work on music theory. Generalizing a theorem of Clough and Douthett, we prove that a finite, simple, connected graph is distance degree regular if and only if whenever a set of vertices has minimal energy, its complement also has minimal energy. We also provide several characterizations of sets of vertices in finite paths and cycles for which the sum of all pairwise distances between vertices in the set is maximal among all sets of the same size.
title Sets of vertices with extremal energy
topic Combinatorics
05C09, 05C12, 05C35, 05C69
url https://arxiv.org/abs/2407.18785