Reconstruction of C_4-free graphs from the set of closed neighborhoods and digital convexity

Fuente: arXiv
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Main Authors: Borgwardt, Steffen, Carr, MacKenzie, Chen, Ce, Ge, Wayne, Hartke, Stephen G., Huang, Yixuan, Moon, Alex
Format: Preprint
Published: 2025
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author Borgwardt, Steffen
Carr, MacKenzie
Chen, Ce
Ge, Wayne
Hartke, Stephen G.
Huang, Yixuan
Moon, Alex
author_facet Borgwardt, Steffen
Carr, MacKenzie
Chen, Ce
Ge, Wayne
Hartke, Stephen G.
Huang, Yixuan
Moon, Alex
contents Fomin, Kratochvíl, Lokshtanov, Mancini, and Telle showed that every $C_{4}$-free graph is reconstructible from the \emph{multiset} of closed neighborhoods. We strengthen their result proving that every $C_{4}$-free graph is reconstructible from the \emph{set} of closed neighborhoods. This extends the work of Lafrance et al.\ by showing that all $C_{4}$-free graphs, and hence all graphs of girth at least five, are reconstructible from their digitally convex sets. A subset $S$ of vertices in a graph $G$ is digitally convex if, for every vertex $v \notin S$, there is a private neighbor of $v$. We establish that reconstruction from digitally convex sets is equivalent to reconstruction from the set of closed neighborhoods.
format Preprint
id arxiv_https___arxiv_org_abs_2510_21195
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reconstruction of C_4-free graphs from the set of closed neighborhoods and digital convexity
Borgwardt, Steffen
Carr, MacKenzie
Chen, Ce
Ge, Wayne
Hartke, Stephen G.
Huang, Yixuan
Moon, Alex
Combinatorics
05C60, 05C75
Fomin, Kratochvíl, Lokshtanov, Mancini, and Telle showed that every $C_{4}$-free graph is reconstructible from the \emph{multiset} of closed neighborhoods. We strengthen their result proving that every $C_{4}$-free graph is reconstructible from the \emph{set} of closed neighborhoods. This extends the work of Lafrance et al.\ by showing that all $C_{4}$-free graphs, and hence all graphs of girth at least five, are reconstructible from their digitally convex sets. A subset $S$ of vertices in a graph $G$ is digitally convex if, for every vertex $v \notin S$, there is a private neighbor of $v$. We establish that reconstruction from digitally convex sets is equivalent to reconstruction from the set of closed neighborhoods.
title Reconstruction of C_4-free graphs from the set of closed neighborhoods and digital convexity
topic Combinatorics
05C60, 05C75
url https://arxiv.org/abs/2510.21195