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A graph is chordal if it does not contain an induced cycle of length greater than three. We determine the minimum size of a chordal graph with given order and minimum degree. In doing so, we have discovered interesting properties of chordal…

Combinatorics · Mathematics 2024-09-17 Xingzhi Zhan , Leilei Zhang

The boxicity of a graph G is defined as the minimum integer k such that G is an intersection graph of axis-parallel k-dimensional boxes. Chordal bipartite graphs are bipartite graphs that do not contain an induced cycle of length greater…

Combinatorics · Mathematics 2009-06-04 L. Sunil Chandran , Mathew C. Francis , Rogers Mathew

A graph $X$ is said to be chordal bipartite if it is bipartite and contains no induced cycle of length at least $6$. It is proved that if $X$ does not contain bipartite claw as an induced subgraph, then the Weisfeiler-Leman dimension of $X$…

Combinatorics · Mathematics 2021-05-26 Ilia Ponomarenko , Grigory Ryabov

A bipartite graph is chordal bipartite if every cycle of length at least 6 has a chord in it. In this paper, we investigate the structure of $P_5$-free chordal bipartite graphs and show that these graphs have a Nested Neighborhood Ordering,…

Discrete Mathematics · Computer Science 2017-12-27 S Aadhavan , P Renjith , N Sadagopan

In this paper, we propose a characterization of chordal bipartite graphs and an efficient enumeration algorithm for chordal bipartite induced subgraphs. A chordal bipartite graph is a bipartite graph without induced cycles with length six…

Data Structures and Algorithms · Computer Science 2020-09-23 Kazuhiro Kurita , Kunihiro Wasa , Hiroki Arimura , Takeaki Uno

A graph is near-bipartite if its vertex set can be partitioned into an independent set and a set which induces a forest. In this paper, planar graphs without cycles of length from 4 to 7 are shown to be near-bipartite.

Combinatorics · Mathematics 2022-04-21 Lili Hao , Weihua Yang , Shuang Zhao

We present an algorithm for determining whether a bipartite graph $G$ is 2-chordal (formerly doubly chordal bipartite). At its core this algorithm is an extension of the existing efficient algorithm for determining whether a graph is…

Combinatorics · Mathematics 2021-04-13 Austin Alderete

The mirror (or bipartite complement) mir(B) of a bipartite graph B=(X,Y,E) has the same color classes X and Y as B, and two vertices x in X and y in Y are adjacent in mir(B) if and only if xy is not in E. A bipartite graph is chordal…

Discrete Mathematics · Computer Science 2013-09-24 Anne Berry , Andreas Brandstädt , Konrad Engel

Chordal graphs are the graphs in which every cycle of length at least four has a chord. A set $S$ is a vertex separator for vertices $a$ and $b$ if the removal of $S$ of the graph separates $a$ and $b$ into distinct connected components. A…

Discrete Mathematics · Computer Science 2018-03-22 Sérgio H. Nogueira , Vinicius F. dos Santos

We study two variations of the Gyarfas--Lehel conjecture on the minimum number of monochromatic components needed to cover an edge-coloured complete bipartite graph. Specifically, we show the following. - For p>> (\log n/n)^{1/2},…

Combinatorics · Mathematics 2024-03-20 Camila Fernández , Matías Pavez-Signé , Maya Stein

Recently, the problem of establishing bounds on the edge density of 1-planar graphs, including their subclass IC-planar graphs, has received considerable attention. In 2018, Angelini et al. showed that any n-vertex bipartite IC-planar graph…

Combinatorics · Mathematics 2025-06-03 Guiping Wang , Yuanqiu Huang , Zhangdong Ouyang , Licheng Zhang

A graph is {\em near-bipartite} if its vertex set can be partitioned into an independent set and a set that induces a forest. It is clear that near-bipartite graphs are $3$-colorable. In this note, we show that planar graphs without cycles…

Combinatorics · Mathematics 2021-06-02 Runrun Liu , Gexin Yu

In the first part of this paper we determine the maximum size of a (finite, simple, connected) bipartite graph of given order, diameter $d$, and connectivity $\kappa$. It was shown by Ali, Mazorodze, Mukwembi and Vetr\'ik [On size, order,…

Combinatorics · Mathematics 2025-09-03 Sonwabile Mafunda

A bipartite graph is chordal bipartite if every cycle of length at least six has a chord in it. M$\ddot{\rm u}$ller \cite {muller1996Hamiltonian} has shown that the Hamiltonian cycle problem is NP-complete on chordal bipartite graphs by…

Discrete Mathematics · Computer Science 2021-07-13 S. Aadhavan , R. Mahendra Kumar , P. Renjith , N. Sadagopan

A bihole in a bipartite graph $G$ with partite sets $A$ and $B$ is an independent set $I$ in $G$ with $|I\cap A|=|I\cap B|$. We prove lower bounds on the largest order of biholes in balanced bipartite graphs subject to conditions involving…

Combinatorics · Mathematics 2020-04-13 Stefan Ehard , Elena Mohr , Dieter Rautenbach

A chorded cycle is a cycle with at least one chord. Gould asked in [Graphs Comb. 38 (2022) 189] the question: What spectral conditions imply a graph contains a chorded cycle? For a graph with fixed size, extremal spectral conditions are…

Combinatorics · Mathematics 2024-08-09 Jin Cai , Leyou Xu , Bo Zhou

A graph is chordal if every cycle of length at least four contains a chord, that is, an edge connecting two nonconsecutive vertices of the cycle. Several classical applications in sparse linear systems, database management, computer vision,…

Data Structures and Algorithms · Computer Science 2016-12-07 David Bergman , Carlos H. Cardonha , Andre A. Cire , Arvind U. Raghunathan

A bipartite covering of a (multi)graph $G$ is a collection of bipartite graphs, so that each edge of $G$ belongs to at least one of them. The capacity of the covering is the sum of the numbers of vertices of these bipartite graphs. In this…

Combinatorics · Mathematics 2023-08-01 Noga Alon

We prove that a complete bipartite graph can be decomposed into cycles of arbitrary specified lengths provided that the obvious necessary conditions are satisfied, the length of each cycle is at most the size of the smallest part, and the…

Combinatorics · Mathematics 2012-04-17 Daniel Horsley

The {\em bipartite-hole-number} of a graph $G$, denoted as $\widetilde\alpha(G)$, is the minimum number $k$ such that there exist integers $a$ and $b$ with $a + b = k+1$ such that for any two disjoint sets $A, B \subseteq V(G)$, there is an…

Combinatorics · Mathematics 2025-11-04 Mark Ellingham , Yixuan Huang , Bing Wei
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