A Classification of Graphs through Quadratic Embedding Constants and Clique Graph Insights

Fuente: arXiv
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Autori principali: Baskoro, Edy Tri, Obata, Nobuaki
Natura: Preprint
Pubblicazione: 2023
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author Baskoro, Edy Tri
Obata, Nobuaki
author_facet Baskoro, Edy Tri
Obata, Nobuaki
contents The quadratic embedding constant (QEC) of a graph $G$ is a new numeric invariant, which is defined in terms of the distance matrix and is denoted by $\mathrm{QEC}(G)$. By observing graph structure of the maximal cliques (clique graph), we show that a graph $G$ with $\mathrm{QEC}(G)<-1/2$ admits a ``cactus-like'' structure. We derive a formula for the quadratic embedding constant of a graph consisting of two maximal cliques. As an application we discuss characterization of graphs along the increasing sequence of $\mathrm{QEC}(P_d)$, where $P_d$ is the path on $d$ vertices. In particular, we determine graphs $G$ satisfying $\mathrm{QEC}(G)<\mathrm{QEC}(P_5)$.
format Preprint
id arxiv_https___arxiv_org_abs_2311_03342
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Classification of Graphs through Quadratic Embedding Constants and Clique Graph Insights
Baskoro, Edy Tri
Obata, Nobuaki
Combinatorics
primary 05C50, secondary 05C12, 05C76
The quadratic embedding constant (QEC) of a graph $G$ is a new numeric invariant, which is defined in terms of the distance matrix and is denoted by $\mathrm{QEC}(G)$. By observing graph structure of the maximal cliques (clique graph), we show that a graph $G$ with $\mathrm{QEC}(G)<-1/2$ admits a ``cactus-like'' structure. We derive a formula for the quadratic embedding constant of a graph consisting of two maximal cliques. As an application we discuss characterization of graphs along the increasing sequence of $\mathrm{QEC}(P_d)$, where $P_d$ is the path on $d$ vertices. In particular, we determine graphs $G$ satisfying $\mathrm{QEC}(G)<\mathrm{QEC}(P_5)$.
title A Classification of Graphs through Quadratic Embedding Constants and Clique Graph Insights
topic Combinatorics
primary 05C50, secondary 05C12, 05C76
url https://arxiv.org/abs/2311.03342