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A word-representable graph is a simple graph $G$ which can be represented by a word $w$ over the vertices of $G$ such that any two vertices are adjacent in $G$ if and only if they alternate in $w$. It is known that the class of…

Discrete Mathematics · Computer Science 2021-09-09 Khyodeno Mozhui , K. V. Krishna

In this work, we show that the class of word-representable graphs is closed under split recomposition and determine the representation number of the graph obtained by recomposing two word-representable graphs. Accordingly, we show that the…

Discrete Mathematics · Computer Science 2024-01-05 Tithi Dwary , K. V. Krishna

While the problem of determining the representation number of an arbitrary word-representable graph is NP-hard, this problem is open even for bipartite graphs. The representation numbers are known for certain bipartite graphs including all…

Combinatorics · Mathematics 2025-06-03 Khyodeno Mozhui , 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

We introduce a new notation for representing labeled regular bipartite graphs of arbitrary degree. Several enumeration problems for labeled and unlabeled regular bipartite graphs have been introduced. A general algorithm for enumerating all…

Discrete Mathematics · Computer Science 2015-12-31 Vivek S. Nittoor

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 $xy$ is an edge in $E$. It is known that any word-representable graph $G$ is…

Combinatorics · Mathematics 2016-09-05 Marc Glen , Sergey Kitaev , Artem Pyatkin

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

We consider the bipartite version of the degree/diameter problem, namely, given natural numbers {\Delta} \geq 2 and D \geq 2, find the maximum number Nb({\Delta},D) of vertices in a bipartite graph of maximum degree {\Delta} and diameter D.…

Combinatorics · Mathematics 2014-05-06 Ramiro Feria-Purón , Guillermo Pineda-Villavicencio

A graph $G = (V, E)$ is said to be word-representable if there exists a word $w$ over the alphabet $V$ such that, for any two distinct letters $x, y \in V$, the letters $x$ and $y$ alternate in $w$ if and only if $xy \in E$. A graph is…

Combinatorics · Mathematics 2025-09-04 Biswajit Das , Ramesh Hariharasubramanian

The modelling of interconnection networks by graphs motivated the study of several extremal problems that involve well known parameters of a graph (degree, diameter, girth and order) and ask for the optimal value of one of them while…

Combinatorics · Mathematics 2020-05-07 Gabriela Araujo-Pardo , Nacho López

The notion of word-representable graphs is a generalization of comparability graphs, in which graphs are represented by words. The complexity of word-representation of a word-representable graph is captured through the representation…

Combinatorics · Mathematics 2026-02-17 Khyodeno Mozhui , K. V. Krishna

Beyond-planarity focuses on combinatorial properties of classes of non-planar graphs that allow for representations satisfying certain local geometric or topological constraints on their edge crossings. Beside the study of a specific graph…

Data Structures and Algorithms · Computer Science 2019-08-27 Patrizio Angelini , Michael A. Bekos , Michael Kaufmann , Thomas Schneck

A split graph is a graph whose vertex set can be partitioned into a clique and an independent set. The word-representability of split graphs was studied in a series of papers in the literature, and the class of word-representable split…

Combinatorics · Mathematics 2025-04-29 Tithi Dwary , Khyodeno Mozhui , K. V. Krishna

Graph representation learning is a ubiquitous task in machine learning where the goal is to embed each vertex into a low-dimensional vector space. We consider the bipartite graph and formalize its representation learning problem as a…

Machine Learning · Statistics 2020-03-03 Sen Na , Yuwei Luo , Zhuoran Yang , Zhaoran Wang , Mladen Kolar

Topological drawings are natural representations of graphs in the plane, where vertices are represented by points, and edges by curves connecting the points. Topological drawings of complete graphs and of complete bipartite graphs have been…

Computational Geometry · Computer Science 2017-02-10 Jean Cardinal , Stefan Felsner

We consider the bipartite version of the {\it degree/diameter problem}, namely, given natural numbers $d\ge2$ and $D\ge2$, find the maximum number $\N^b(d,D)$ of vertices in a bipartite graph of maximum degree $d$ and diameter $D$. In this…

Combinatorics · Mathematics 2014-05-06 Ramiro Feria-Puron , Mirka Miller , Guillermo Pineda-Villavicencio

The class of bipartite permutation graphs enjoys many nice and important properties. In particular, this class is critically important in the study of clique- and rank-width of graphs, because it is one of the minimal hereditary classes of…

Combinatorics · Mathematics 2020-10-28 Bogdan Alecu , Vadim Lozin , Dmitriy Malyshev

For bipartite graphs the NP-completeness is proved for the problem of existence of maximum matching which removal leads to a graph with given lower(upper)bound for the cardinality of its maximum matching.

Discrete Mathematics · Computer Science 2008-03-08 R. R. Kamalian , V. V. Mkrtchyan

An \emph{outer-string representation} of a graph $G$ is an intersection representation of $G$ where vertices are represented by curves (strings) inside the unit disk and each curve has exactly one endpoint on the boundary of the unit disk…

Combinatorics · Mathematics 2026-05-18 Todor Antić , Vít Jelínek , Jan Kratochvíl , Peter Stumpf

The approach mapping from a matching of bipartite graphs to digraphs has been successfully used for forcing set problem, in this paper, it is extended to uniquely restricted matching problem. We show to determine a uniquely restricted…

Computational Complexity · Computer Science 2010-09-29 Guohun Zhu
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