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The class of Parikh word representable graphs were recently introduced. In this work, we further develop its general theory beyond the binary alphabet. Our main result shows that this class is equivalent to the class of bipartite…

Combinatorics · Mathematics 2018-12-27 Wen Chean Teh , Zhen Chuan Ng , Muhammad Javaid , Zi Jing Chern

In this paper, we study the word-representability of well-partitioned chordal graphs using split decomposition. We show that every component of the minimal split decomposition of a well-partitioned chordal graph is a split graph. Thus we…

Combinatorics · Mathematics 2025-04-08 Tithi Dwary , K. V. Krishna

The graphs with permutation-representation number (\textit{prn}) at most two are known. While a characterization for the class of graphs with the \textit{prn} at most three is an open problem, we summarize the graphs of this class that are…

Discrete Mathematics · Computer Science 2023-10-03 Khyodeno Mozhui , K. V. Krishna

Distinct letters $x$ and $y$ alternate in a word $w$ if after deleting in $w$ all letters but the copies of $x$ and $y$ we either obtain a word of the form $xyxy\cdots$ (of even or odd length) or a word of the form $yxyx\cdots$ (of even or…

Combinatorics · Mathematics 2019-07-23 Gi-Sang Cheon , Jinha Kim , Minki Kim , Sergey Kitaev

A graph $G=(V,E)$ is word-representable if there exists a word $w$ over the alphabet $V$ such that letters $x$ and $y$ alternate in $w$ if and only if $(x,y)\in E$. A triangular grid graph is a subgraph of a tiling of the plane with…

Combinatorics · Mathematics 2015-03-30 Zongqing Chen , Sergey Kitaev , Brian Y. Sun

In this work, we introduce a new notion for representing graph classes with formal languages. In contrast to the seminal work by Kitaev and Pyatkin to represent graphs by words, we use formal binary languages in order to have a set of…

Formal Languages and Automata Theory · Computer Science 2026-04-22 Henning Fernau , Pamela Fleischmann , Kevin Mann , Silas Cato Sacher

We propose a new approach to text semantic analysis and general corpus analysis using, as termed in this article, a "bi-gram graph" representation of a corpus. The different attributes derived from graph theory are measured and analyzed as…

Machine Learning · Computer Science 2021-07-30 Thomas Konstantinovsky , Matan Mizrachi

Recently, Jones et al. introduced the study of $u$-representable graphs, where $u$ is a word over $\{1,2\}$ containing at least one 1. The notion of a $u$-representable graph is a far-reaching generalization of the notion of a…

Combinatorics · Mathematics 2015-07-19 Sergey Kitaev

A graph $G=(V,E)$ is word-representable if there exists a word $w$ over the alphabet $V$ such that letters $x$ and $y$ alternate in $w$ if and only if $(x,y)$ is an edge in $E$. Some graphs are word-representable, others are not. It is…

Combinatorics · Mathematics 2014-05-15 Prosper Akrobotu , Sergey Kitaev , Zuzana Masárová

A 1-11-representation of a graph $G(V,E)$ is a word over the alphabet $V$ such that two distinct vertices $x$ and $y$ are adjacent if and only if the restricted word $w{x,y}$ (obtained from $w$ by deleting all letters except $x$ and $y$)…

Combinatorics · Mathematics 2026-01-29 Biswajit Das , Ramesh Hariharasubramanian

The class of word-representable graphs, introduced in connection with the study of the Perkins semigroup by Kitaev and Seif, has attracted significant attention in combinatorics and theoretical computer science due to its deep connections…

Combinatorics · Mathematics 2025-12-16 Eshwar Srinivasan , Ramesh Hariharasubramanian

In this paper, we discuss a method for identifying a seed word that would best represent a class of named entities in a graphical representation of words and their similarities. Word networks, or word graphs, are representations of…

Computation and Language · Computer Science 2018-07-13 Miguel Feria , Juan Paolo Balbin , Francis Michael Bautista

Word-representable graphs, characterized by the existence of a semi-transitive orientation, form a well-studied class of graphs. Comparability graphs form another well-studied class and constitute a subclass of word-representable graphs.…

Discrete Mathematics · Computer Science 2026-05-15 Benny George Kenkireth , Gopalan Sajith , Sreyas Sasidharan

A graph $G=(V,E)$ is representable if there exists a word $W$ over the alphabet $V$ such that letters $x$ and $y$ alternate in $W$ if and only if $(x,y)\in E$ for each $x\neq y$. If $W$ is $k$-uniform (each letter of $W$ occurs exactly $k$…

Combinatorics · Mathematics 2008-10-03 Magnus Mar Halldorsson , Sergey Kitaev , Artem Pyatkin

A graph $G=(V,E)$ is word-representable if there exists a word $w$ over the alphabet $V$ such that letters $x$ and $y$, $x\neq y$, alternate in $w$ if and only if $(x,y)\in E$. Halld\'{o}rsson et al.\ have shown that a graph is…

Combinatorics · Mathematics 2015-08-03 Thomas Z. Q. Chen , Sergey Kitaev , Brian Y. Sun

Jeff Remmel introduced the concept of a $k$-11-representable graph in 2017. This concept was first explored by Cheon et al. in 2019, who considered it as a natural extension of word-representable graphs, which are exactly 0-11-representable…

Combinatorics · Mathematics 2025-01-24 Mohammed Alshammari , Sergey Kitaev , Chaoliang Tang , Tianyi Tao , Junchi Zhang

Jones et al. (2015) introduced the notion of $u$-representable graphs, where $u$ is a word over $\{1, 2\}$ different from $22\cdots2$, as a generalization of word-representable graphs. Kitaev (2016) showed that if $u$ is of length at least…

Discrete Mathematics · Computer Science 2022-12-20 Asahi Takaoka

The notion of a $p$-Riordan graph generalizes that of a Riordan graph, which, in turn, generalizes the notions of a Pascal graph and a Toeplitz graph. In this paper we introduce the notion of a $p$-Riordan word, and show how to encode…

Combinatorics · Mathematics 2020-09-04 Kittitat Iamthong , Ji-Hwan Jung , Sergey Kitaev

In this article we give two different ways of representations of circular words. Representations with tuples are intended as a compact notation, while representations with trees give a way to easily process all conjugates of a word. The…

Formal Languages and Automata Theory · Computer Science 2014-05-23 László Hegedüs , Benedek Nagy

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…

Combinatorics · Mathematics 2026-05-26 Suchanda Roy , Ramesh Hariharasubramanian