Characterization of Word-Representable Near-Triangulations

Fuente: arXiv
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Autori principali: Roy, Suchanda, Hariharasubramanian, Ramesh
Natura: Preprint
Pubblicazione: 2026
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author Roy, Suchanda
Hariharasubramanian, Ramesh
author_facet Roy, Suchanda
Hariharasubramanian, Ramesh
contents A graph $G=(V,E)$ is said to be word-representable if there exists a word $w$ over the alphabet $V$ such that two distinct letters $x,y\in V$ alternate in $w$ if and only if $xy \in E$. Word-representable graphs form a well-studied graph class with connections to graph orientations, combinatorics on words, and graph coloring. A near-triangulation is a planar graph in which every face except the outer face is a triangle. Several subclasses of near-triangulations have previously been investigated in the context of word-representability, including polyomino triangulations, triangulations of rectangular polyominoes with a single domino tile, $K_4$-free near-triangulations, face subdivisions of triangular grid graphs, triangulations of grid-covered cylinder graphs, and chordal near-triangulations. In this paper, we obtain a complete characterization of word-representable near-triangulations in terms of forbidden induced subgraphs. Our result unifies and extends the previously known characterizations for the above subclasses, while also correcting inaccuracies appearing in earlier works.
format Preprint
id arxiv_https___arxiv_org_abs_2605_25733
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Characterization of Word-Representable Near-Triangulations
Roy, Suchanda
Hariharasubramanian, Ramesh
Combinatorics
Discrete Mathematics
A graph $G=(V,E)$ is said to be word-representable if there exists a word $w$ over the alphabet $V$ such that two distinct letters $x,y\in V$ alternate in $w$ if and only if $xy \in E$. Word-representable graphs form a well-studied graph class with connections to graph orientations, combinatorics on words, and graph coloring. A near-triangulation is a planar graph in which every face except the outer face is a triangle. Several subclasses of near-triangulations have previously been investigated in the context of word-representability, including polyomino triangulations, triangulations of rectangular polyominoes with a single domino tile, $K_4$-free near-triangulations, face subdivisions of triangular grid graphs, triangulations of grid-covered cylinder graphs, and chordal near-triangulations. In this paper, we obtain a complete characterization of word-representable near-triangulations in terms of forbidden induced subgraphs. Our result unifies and extends the previously known characterizations for the above subclasses, while also correcting inaccuracies appearing in earlier works.
title Characterization of Word-Representable Near-Triangulations
topic Combinatorics
Discrete Mathematics
url https://arxiv.org/abs/2605.25733