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Main Authors: Moondra, Jai, Sahdev, Aditya, Tripathi, Amitabha
Format: Preprint
Published: 2020
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Online Access:https://arxiv.org/abs/2009.10294
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author Moondra, Jai
Sahdev, Aditya
Tripathi, Amitabha
author_facet Moondra, Jai
Sahdev, Aditya
Tripathi, Amitabha
contents The degree set of a finite simple graph $G$ is the set of distinct degrees of vertices of $G$. A theorem of Kapoor, Polimeni & Wall asserts that the least order of a graph with a given degree set $\mathscr D$ is $1+\max \mathscr D$. Tripathi & Vijay considered the analogous problem concerning the least size of graphs with degree set $\mathscr D$. We expand on their results, and determine the least size of graphs with degree set $\mathscr D$ when (i) $\min \mathscr D \mid d$ for each $d \in \mathscr D$; (ii) $\min \mathscr D=2$; (iii) $\mathscr D=\{m,m+1,\ldots,n\}$. In addition, given any $\mathscr D$, we produce a graph $G$ whose size is within $\min \mathscr D$ of the optimal size, giving a $\big(1+\frac{2}{d_1+1})$-approximation, where $d_1=\max \mathscr D$.
format Preprint
id arxiv_https___arxiv_org_abs_2009_10294
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle On the least size of a graph with a given degree set -- II
Moondra, Jai
Sahdev, Aditya
Tripathi, Amitabha
Combinatorics
05C07
The degree set of a finite simple graph $G$ is the set of distinct degrees of vertices of $G$. A theorem of Kapoor, Polimeni & Wall asserts that the least order of a graph with a given degree set $\mathscr D$ is $1+\max \mathscr D$. Tripathi & Vijay considered the analogous problem concerning the least size of graphs with degree set $\mathscr D$. We expand on their results, and determine the least size of graphs with degree set $\mathscr D$ when (i) $\min \mathscr D \mid d$ for each $d \in \mathscr D$; (ii) $\min \mathscr D=2$; (iii) $\mathscr D=\{m,m+1,\ldots,n\}$. In addition, given any $\mathscr D$, we produce a graph $G$ whose size is within $\min \mathscr D$ of the optimal size, giving a $\big(1+\frac{2}{d_1+1})$-approximation, where $d_1=\max \mathscr D$.
title On the least size of a graph with a given degree set -- II
topic Combinatorics
05C07
url https://arxiv.org/abs/2009.10294