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Strongly chordal digraphs are included in the class of chordal digraphs and generalize strongly chordal graphs and chordal bipartite graphs. They are the digraphs that admit a linear ordering of its vertex set for which their adjacency…

Combinatorics · Mathematics 2025-09-24 Pavol Hell , César Hernández-Cruz , Jing Huang

We introduce the class of strong cocomparability graphs, as the class of reflexive graphs whose adjacency matrix can be rearranged by a simultaneous row and column permutation to avoid the submatrix with rows 01, 10, which we call Slash. We…

Combinatorics · Mathematics 2022-11-01 Pavol Hell , Jing Huang , Jephian C. -H. Lin

Strongly chordal graphs are a subclass of chordal graphs. The interest in this subclass stems from the fact that many problems which are NP-complete for chordal graphs are solvable in polynomial time for this subclass. However, we are not…

Data Structures and Algorithms · Computer Science 2018-04-25 Md. Zamilur Rahman , Asish Mukhopadhyay , Yash P. Aneja

Chordal graphs are important in algorithmic graph theory. Chordal digraphs are a digraph analogue of chordal graphs and have been a subject of active studies recently. Unlike chordal graphs, chordal digraphs lack many structural properties…

Combinatorics · Mathematics 2022-11-29 Jing Huang , Ying Ying Ye

In this paper, motivated by a question posed in \cite{AH}, we introduce strongly biconvex graphs as a subclass of weakly chordal and bipartite graphs. We give a linear time algorithm to find an induced matching for such graphs and we prove…

Commutative Algebra · Mathematics 2019-05-08 Sara Saeedi Madani , Dariush Kiani

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

For any class $\mathcal{C}$ of bipartite graphs, we define quasi-$\cal C$ to be the class of all graphs $G$ such that every bipartition of $G$ belongs to $\cal C$. This definition is motivated by a generalisation of the switch Markov chain…

Discrete Mathematics · Computer Science 2018-02-27 Martin Dyer , Haiko Müller

We study the class of 1-perfectly orientable graphs, that is, graphs having an orientation in which every out-neighborhood induces a tournament. 1-perfectly orientable graphs form a common generalization of chordal graphs and circular arc…

Combinatorics · Mathematics 2016-03-08 Tatiana Romina Hartinger , Martin Milanič

In this paper we deal with a subclass of chordal graphs, which are simultaneously strictly chordal and interval, the strictly interval graphs. We present a new characterization of the class that leads to a simple linear recognition…

Discrete Mathematics · Computer Science 2026-05-19 Claudia Justel , Lilian Markenzon

Minimal separators in graphs are an important concept in algorithmic graph theory. In particular, many problems that are NP-hard for general graphs are known to become polynomial-time solvable for classes of graphs with a polynomially…

Combinatorics · Mathematics 2019-06-03 Martin Milanič , Nevena Pivač

Strongly chordal graphs are a subclass of chordal graphs. Farber also established a number of different characterisations for this class of graphs. These include an intersection graph characterisation that is analogous to a similar…

Data Structures and Algorithms · Computer Science 2019-09-06 Md. Zamilur Rahman , Asish Mukhopadhyay

Strong cocomparability graphs are the reflexive graphs whose adjacency matrix can be rearranged by a simultaneous row and column permutation to avoid the submatrix with rows $01, 10$. Strong cocomparability graphs form a subclass of…

Combinatorics · Mathematics 2023-04-04 Jing Huang

We introduce a new subclass of chordal graphs that generalizes split graphs, which we call well-partitioned chordal graphs. Split graphs are graphs that admit a partition of the vertex set into cliques that can be arranged in a star…

Combinatorics · Mathematics 2020-02-26 Jungho Ahn , Lars Jaffke , O-joung Kwon , Paloma T. Lima

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

Enumerating minimal dominating sets with polynomial delay in bipartite graphs is a long-standing open problem. To date, even the subcase of chordal bipartite graphs is open, with the best known algorithm due to Golovach, Heggernes, Kant\'e,…

Data Structures and Algorithms · Computer Science 2025-08-05 Emanuel Castelo , Oscar Defrain , Guilherme C. M. Gomes

We introduce a new class of structured symmetric matrices by extending the notion of perfect elimination ordering from graphs to weighted graphs or matrices. This offers a common framework capturing common vertex elimination orderings of…

Combinatorics · Mathematics 2018-11-20 Monique Laurent , Shin-ichi Tanigawa

The commuting graph of a group $G$ is the graph whose vertices are the elements of $G$, two distinct vertices joined if they commute. Our purpose in this paper is twofold: we discuss the computational problem of deciding whether a given…

Group Theory · Mathematics 2025-07-29 V. Arvind , Xuanlong Ma , Peter J. Cameron , Natalia V. Maslova

Given a 0-1 square matrix A, when can some of the 1's be changed to -1's in such a way that the permanent of A equals the determinant of the modified matrix? When does a real square matrix have the property that every real matrix with the…

Combinatorics · Mathematics 2016-09-07 Neil Robertson , P. D. Seymour , Robin Thomas

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

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
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