English
Related papers

Related papers: Critical Equimatchable Graphs

200 papers

A vertex $v$ of a 2-connected cubic graph $G$ is $\lambda$-matchable if $G$ has a spanning subgraph in which $v$ has degree three whereas every other vertex has degree one, and we let $\lambda(G)$ denote the number of such vertices.…

Combinatorics · Mathematics 2025-10-15 Santhosh Raghul , Nishad Kothari

A bridgeless graph $G$ is called $3$-flow-critical if it does not admit a nowhere-zero $3$-flow, but $G/e$ has for any $e\in E(G)$. Tutte's $3$-flow conjecture can be equivalently stated as that every $3$-flow-critical graph contains a…

Combinatorics · Mathematics 2020-03-23 Jiaao Li , Yulai Ma , Yongtang Shi , Weifan Wang , Yezhou Wu

A $c$-crossing-critical graph is one that has crossing number at least $c$ but each of its proper subgraphs has crossing number less than $c$. Recently, a set of explicit construction rules was identified by Bokal, Oporowski, Richter, and…

Discrete Mathematics · Computer Science 2021-12-10 Drago Bokal , Markus Chimani , Alexander Nover , Jöran Schierbaum , Tobias Stolzmann , Mirko H. Wagner , Tilo Wiedera

A matching cut in a graph G is an edge cut of G that is also a matching. This short survey gives an overview of old and new results and open problems for Maximum Matching Cut, which is to determine the size of a largest matching cut in a…

Combinatorics · Mathematics 2023-12-21 Van Bang Le , Felicia Lucke , Daniël Paulusma , Bernard Ries

A path $P$ in an edge-colored graph is called \emph{a conflict-free path} if there exists a color used on only one of the edges of $P$. An edge-colored graph $G$ is called \emph{conflict-free connected} if for each pair of distinct vertices…

Combinatorics · Mathematics 2019-01-25 Meng Ji , Xueliang Li

A graph is said to be globally rigid if almost all embeddings of the graph's vertices in the Euclidean plane will define a system of edge-length equations with a unique (up to isometry) solution. In 2007, Jackson, Servatius and Servatius…

Combinatorics · Mathematics 2024-01-29 Sean Dewar

We call a finite undirected graph minimally k-matchable if it has at least k distinct perfect matchings but deleting any edge results in a graph which has not. An odd subdivision of some graph G is any graph obtained by replacing every edge…

Combinatorics · Mathematics 2016-08-05 Gasper Fijavz , Matthias Kriesell

Driven by many applications in graph analytics, the problem of computing $k$-edge connected components ($k$-ECCs) of a graph $G$ for a user-given $k$ has been extensively studied recently. In this paper, we investigate the problem of…

Data Structures and Algorithms · Computer Science 2017-11-29 Lijun Chang

An unfriendly partition of a graph $G = (V,E)$ is a function $c: V \to 2$ such that $|\{x\in N(v): c(x)\neq c(v)\}|\geq |\{x\in N(v): c(x)=c(v)\}|$ for every vertex $v\in V$, where $N(v)$ denotes its neighborhood. It was conjectured by…

Combinatorics · Mathematics 2023-04-06 Leandro Fiorini Aurichi , Lucas Real

A graph is said to be a Konig graph if the size of its maximum matching is equal to the size of its minimum vertex cover. The Konig Edge Deletion problem asks if in a given graph there exists a set of at most k edges whose deletion results…

Data Structures and Algorithms · Computer Science 2019-09-26 Diptapriyo Majumdar , Rian Neogi , Venkatesh Raman , S. Vaishali

A $k$-{\it edge-weighting} $w$ of a graph $G$ is an assignment of an integer weight, $w(e)\in \{1,\dots, k\}$, to each edge $e$. An edge weighting naturally induces a vertex coloring $c$ by defining $c(u)=\sum_{u\sim e} w(e)$ for every $u…

Combinatorics · Mathematics 2010-07-13 Hongliang Lu , Qinglin Yu , Cun-Quan Zhang

Let $ G=(V,E) $ be a simple graph of order $ n $ and size $ m $. A connected edge cover set of a graph is a subset $S$ of edges such that every vertex of the graph is incident to at least one edge of $S$ and the subgraph induced by $S$ is…

Combinatorics · Mathematics 2024-12-23 Mahsa Zare , Saeid Alikhani , Mohammad Reza Oboudi

For most problems pertaining to perfect matchings, one may restrict attention to matching covered graphs - that is, connected nontrivial graphs with the property that each edge belongs to some perfect matching. There is extensive literature…

Combinatorics · Mathematics 2025-05-21 Aditya Y Dalwadi , Kapil R Shenvi Pause , Ajit A Diwan , Nishad Kothari

We say a hypergraph $\mathcal{H}$ contains a graph $G$ as trace if there exists a vertex subset $S \subseteq V(\mathcal{H})$ such that $|S| = V(G)$ and $\{e \cap S \mid e \in E(\mathcal{H})\}$ contains $G$ as a subgraph. We use…

Combinatorics · Mathematics 2026-03-03 Yichen Wang , Xin Cheng , Ervin Győri , Yuanpei Wang , Xiamiao Zhao , Junpeng Zhou

The stability number of a graph G, denoted by alpha(G), is the cardinality of a stable set of maximum size in G. If alpha(G-e) > alpha(G), then e is an alpha-critical edge, and if mu(G-e) < mu(G), then e is a mu-critical edge, where mu(G)…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

Berge Conjecture states that every bridgeless cubic graph has 5 perfect matchings such that each edge is contained in at least one of them. In this paper, we show that Berge Conjecture holds for two classes of cubic graphs, cubic graphs…

Combinatorics · Mathematics 2016-03-01 Wuyang Sun

Let $V$ be a set of cardinality $v$ (possibly infinite). Two graphs $G$ and $G'$ with vertex set $V$ are {\it isomorphic up to complementation} if $G'$ is isomorphic to $G$ or to the complement $\bar G$ of $G$. Let $k$ be a non-negative…

Combinatorics · Mathematics 2016-08-16 Jamel Dammak , Gérard Lopez , Maurice Pouzet , Hamza Si Kaddour

Given two graphs G and H its 1-{\it join} is the graph obtained by taking the disjoint union of G and H and adding all the edges between a nonempty subset of vertices of G and a nonempty subset of vertices of H. In general, composition…

Combinatorics · Mathematics 2007-07-30 Carlos E. Valencia , Marcos I. Barrita

A graph $G$ is said to be perfectly divisible if for every induced subgraph $H$ of $G$ with at least one edge, the vertex set $V(H)$ can be partitioned into two sets $A, B$ such that $H[A]$ is perfect and $\omega(B) < \omega(H)$. It is easy…

Combinatorics · Mathematics 2026-05-12 Hongzhang Chen , Kaiyang Lan , Wenlong Zhong

Edge-weighted graphs play an important role in the theory of Robinsonian matrices and similarity theory, particularly via the concept of level graphs, that is, graphs obtained from an edge-weighted graph by removing all sufficiently light…