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Related papers: Word-representability of co-bipartite graph

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A graph with vertex set V and edge set E is called a (d,c)-expander if the maximum degree of a vertex is d and, for every subset W of V that has cardinality at most |V|/2, the number of edges between vertices in W and vertices outside of W…

Combinatorics · Mathematics 2007-05-23 Lars Engebretsen

A bipartite graph $G=(A, B, E)$ is said to be a biconvex bipartite graph if there exist orderings $<_A$ in $A$ and $<_B$ in $B$ such that the neighbors of every vertex in $A$ are consecutive with respect to $<_B$ and the neighbors of every…

Combinatorics · Mathematics 2024-06-04 Dhanyamol Antony , Anita Das , Shirish Gosavi , Dalu Jacob , Shashanka Kulamarva

A multifamily set representation of a finite simple graph $G$ is a multifamily $\mathcal{F}$ of sets (not necessarily distinct) for which each set represents a vertex in $G$ and two sets in $\mathcal{F}$ intersects if and only if the two…

Combinatorics · Mathematics 2008-04-30 Tao-Ming Wang , Jun-Lin Kuo

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

A half-square of a bipartite graph $B=(X,Y,E_B)$ has one color class of $B$ as vertex set, say $X$; two vertices are adjacent whenever they have a common neighbor in $Y$. If $G=(V,E_G)$ is the half-square of a planar bipartite graph…

Discrete Mathematics · Computer Science 2018-12-12 Hoang-Oanh Le , Van Bang Le

An $(r, \ell)$-partition of a graph $G$ is a partition of its vertex set into $r$ independent sets and $\ell$ cliques. A graph is $(r, \ell)$ if it admits an $(r, \ell)$-partition. A graph is well-covered if every maximal independent set is…

Data Structures and Algorithms · Computer Science 2018-06-07 Sancrey R. Alves , Konrad K. Dabrowski , Luerbio Faria , Sulamita Klein , Ignasi Sau , Uéverton S. Souza

The paper consider an equivalence relation in the set of vertices of a bipartite graph. Some numerical characteristics showing the cardinality of equivalence classes are introduced. A combinatorial identity that is in relationship to these…

Combinatorics · Mathematics 2014-04-28 Krasimir Yordzhev

In this work, we investigate the relationship between $k$-repre\-sentable graphs and graphs representable by $k$-local words. In particular, we show that every graph representable by a $k$-local word is $(k+1)$-representable. A previous…

Combinatorics · Mathematics 2025-06-25 Philipp Böll , Pamela Fleischmann , Annika Huch , Jana Kreiß , Tim Löck , Kajus Park , Max Wiedenhöft

Recently, Milani\v{c} and Trotignon introduced the class of equistarable graphs as graphs without isolated vertices admitting positive weights on the edges such that a subset of edges is of total weight $1$ if and only if it forms a maximal…

Combinatorics · Mathematics 2015-02-24 Endre Boros , Nina Chiarelli , Martin Milanič

Word-representable graphs, which are the same as semi-transitively orientable graphs, generalize several fundamental classes of graphs. In this paper we propose a novel approach to study word-representability of graphs using a technique of…

Combinatorics · Mathematics 2023-12-19 Sumin Huang , Sergey Kitaev , Artem Pyatkin

An edge $e$ of a matching covered graph $G$ is removable if $G-e$ is also matching covered. The notion of removable edge arises in connection with ear decompositions of matching covered graphs introduced by Lov\'asz and Plummer. A…

Combinatorics · Mathematics 2024-06-04 Yipei Zhang , Fuliang Lu , Xiumei Wang , Jinjiang Yuan

In \cite{Chan95}, the authors classified the 2-extendable abelian Cayley graphs and posed the problem of characterizing all 2-extendable Cayley graphs. We first show that a connected bipartite Cayley (vertex-transitive) graph is…

Combinatorics · Mathematics 2016-12-12 Qiuli Li , Xing Gao

An open question in the theory of word-representable graphs for the past decade has been whether the line graph of a non-word-representable graph is always non-word-representable. By formulating an appropriate optimization problem for the…

Combinatorics · Mathematics 2021-08-06 M M Akbar , P D Akrobotu , C P Brewer

The biclique partition number $(\text{bp})$ of a graph $G$ is referred to as the least number of complete bipartite (biclique) subgraphs that are required to cover the edges of the graph exactly once. In this paper, we show that the…

Combinatorics · Mathematics 2023-02-17 Bochuan Lyu , Illya V. Hicks

In a graph, a matching cut is an edge cut that is a matching. Matching Cut is the problem of deciding whether or not a given graph has a matching cut, which is known to be NP-complete even when restricted to bipartite graphs. It has been…

Computational Complexity · Computer Science 2018-10-29 Hoang-Oanh Le , Van Bang Le

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

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

Let $\Gamma$ be a $G$-symmetric graph with vertex set $V$. We suppose that $V$ admits a $G$-partition $\mathcal{B} = \{ B_0, ... , B_b \}$, with parts of size $v$, and that the quotient graph induced on $\mathcal B$ is a complete graph of…

Combinatorics · Mathematics 2017-09-06 A. Gardiner , Cheryl E. Praeger

We consider a set of cliques in any multipartite graph with two vertices in each part. Moreover, we construct a class of peculiar polytopes. Key words: multipartite graph, clique, polytope.

Combinatorics · Mathematics 2007-05-23 Julia V. Grishicheva , Alexander V. Seliverstov

In this paper we study graphs defined by pattern-avoiding words. Word-representable graphs have been studied extensively following their introduction in 2000 and are the subject of a book published by Kitaev in 2015. Recently there has been…

Combinatorics · Mathematics 2016-08-30 Yelena Mandelshtam