On Graphs Representable by Pattern-Avoiding Words
Discussiones Mathematicae. Graph Theory, Tome 39 (2019) no. 2, pp. 375-389
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In this paper we study graphs defined by pattern-avoiding words. Word-representable graphs have been studied extensively following their introduction in 2004 and are the subject of a book published by Kitaev and Lozin in 2015. Recently there has been interest in studying graphs represented by pattern-avoiding words. In particular, in 2016, Gao, Kitaev, and Zhang investigated 132-representable graphs, that is, word-representable graphs that can be represented by a word which avoids the pattern 132. They proved that all 132-representable graphs are circle graphs and provided examples and properties of 132-representable graphs. They posed several questions, some of which we answer in this paper.
One of our main results is that not all circle graphs are 132-representable, thus proving that 132-representable graphs are a proper subset of circle graphs, a question that was left open in the paper by Gao et al. We show that 123-representable graphs are also a proper subset of circle graphs, and are different from 132-representable graphs. We also study graphs represented by pattern-avoiding 2-uniform words, that is, words in which every letter appears exactly twice.
Keywords:
pattern-avoidance, word-representability, circle graphs
@article{DMGT_2019_39_2_a6,
author = {Mandelshtam, Yelena},
title = {On {Graphs} {Representable} by {Pattern-Avoiding} {Words}},
journal = {Discussiones Mathematicae. Graph Theory},
pages = {375--389},
publisher = {mathdoc},
volume = {39},
number = {2},
year = {2019},
language = {en},
url = {http://geodesic.mathdoc.fr/item/DMGT_2019_39_2_a6/}
}
Mandelshtam, Yelena. On Graphs Representable by Pattern-Avoiding Words. Discussiones Mathematicae. Graph Theory, Tome 39 (2019) no. 2, pp. 375-389. http://geodesic.mathdoc.fr/item/DMGT_2019_39_2_a6/