Triangle-free graphs with diameter 2

Fuente: arXiv
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Main Authors: Devillers, Alice, Kamčev, Nina, McKay, Brendan, Catháin, Padraig Ó, Royle, Gordon, Van de Voorde, Geertrui, Wanless, Ian, Wood, David R.
Format: Preprint
Published: 2024
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author Devillers, Alice
Kamčev, Nina
McKay, Brendan
Catháin, Padraig Ó
Royle, Gordon
Van de Voorde, Geertrui
Wanless, Ian
Wood, David R.
author_facet Devillers, Alice
Kamčev, Nina
McKay, Brendan
Catháin, Padraig Ó
Royle, Gordon
Van de Voorde, Geertrui
Wanless, Ian
Wood, David R.
contents There are finitely many graphs with diameter $2$ and girth 5. What if the girth 5 assumption is relaxed? Apart from stars, are there finitely many triangle-free graphs with diameter $2$ and no $K_{2,3}$ subgraph? This question is related to the existence of triangle-free strongly regular graphs, but allowing for a range of co-degrees gives the question a more extremal flavour. More generally, for fixed $s$ and $t$, are there infinitely many twin-free triangle-free $K_{s,t}$-free graphs with diameter 2? This paper presents partial results regarding these questions, including computational results, potential Cayley-graph and probabilistic constructions.
format Preprint
id arxiv_https___arxiv_org_abs_2406_00246
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Triangle-free graphs with diameter 2
Devillers, Alice
Kamčev, Nina
McKay, Brendan
Catháin, Padraig Ó
Royle, Gordon
Van de Voorde, Geertrui
Wanless, Ian
Wood, David R.
Combinatorics
There are finitely many graphs with diameter $2$ and girth 5. What if the girth 5 assumption is relaxed? Apart from stars, are there finitely many triangle-free graphs with diameter $2$ and no $K_{2,3}$ subgraph? This question is related to the existence of triangle-free strongly regular graphs, but allowing for a range of co-degrees gives the question a more extremal flavour. More generally, for fixed $s$ and $t$, are there infinitely many twin-free triangle-free $K_{s,t}$-free graphs with diameter 2? This paper presents partial results regarding these questions, including computational results, potential Cayley-graph and probabilistic constructions.
title Triangle-free graphs with diameter 2
topic Combinatorics
url https://arxiv.org/abs/2406.00246