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Lovasz and Plummer conjectured in the 1970's that cubic bridgeless graphs have exponentially many perfect matchings. This conjecture has been verified for bipartite graphs by Voorhoeve in 1979, and for planar graphs by Chudnovsky and…

Combinatorics · Mathematics 2012-06-08 L. Esperet , F. Kardos , D. Kral'

In this paper we study conditions which guarantee the existence of perfect matchings and perfect fractional matchings in uniform hypergraphs. We reduce this problem to an old conjecture by Erd\H{o}s on estimating the maximum number of edges…

Combinatorics · Mathematics 2012-02-01 Noga Alon , Peter Frankl , Hao Huang , Vojtech Rodl , Andrzej Rucinski , Benny Sudakov

A normal odd partition T of the edges of a cubic graph is a partition into trails of odd length (no repeated edge) such that each vertex is the end vertex of exactly one trail of the partition and internal in some trail. For each vertex v,…

Discrete Mathematics · Computer Science 2012-01-30 Jean-Luc Fouquet , Jean-Marie Vanherpe

We present a near-linear-time algorithm that, given a bridgeless cubic graph, finds a perfect matching intersecting every 3-edge-cut in exactly one edge. This improves over a cubic algorithm of Boyd et al. for the same problem, and over our…

Data Structures and Algorithms · Computer Science 2026-05-04 Babak Ghanbari , Robert Šámal

If $G$ and $H$ are two cubic graphs, then we write $H\prec G$, if $G$ admits a proper edge-coloring $f$ with edges of $H$, such that for each vertex $x$ of $G$, there is a vertex $y$ of $H$ with $f(\partial_G(x))=\partial_H(y)$. Let $P$ and…

Discrete Mathematics · Computer Science 2013-05-22 Vahan V. Mkrtchyan

A matching $M$ in a graph $G$ is {\em connected} if $G$ has an edge linking each pair of edges in $M$. The problem to find large connected matchings in graphs $G$ with $\alpha(G)=2$ is closely related to Hadwiger's conjecture for graphs…

Combinatorics · Mathematics 2024-09-11 Rong Chen , Zijian Deng

The restricted hypercube-like graphs, variants of the hypercube, were proposed as desired interconnection networks of parallel systems. The matching preclusion number of a graph is the minimum number of edges whose deletion results in the…

Combinatorics · Mathematics 2020-01-23 Huazhong Lü , Tingzeng Wu

Lov\'asz and Plummer conjectured, in the mid 1970's, that every cubic graph G with no cutedge has an exponential in |V(G)| number of perfect matchings. In this work we show that every cubic planar graph G whose geometric dual graph is a…

Combinatorics · Mathematics 2010-10-29 Andrea Jiménez , Marcos Kiwi

For a graph $G$ and a not necessarily proper $k$-edge coloring $c:E(G)\to \{ 1,\ldots,k\}$, let $m_i(G)$ be the number of edges of $G$ of color $i$, and call $G$ {\it color-balanced} if $m_i(G)=m_j(G)$ for every two colors $i$ and $j$.…

Combinatorics · Mathematics 2021-05-13 Johannes Pardey , Dieter Rautenbach

A triple of vertices in a graph is a \emph{frustrated triangle} if it induces an odd number of edges. We study the set $F_n\subset[0,\binom{n}{3}]$ of possible number of frustrated triangles $f(G)$ in a graph $G$ on $n$ vertices. We prove…

Combinatorics · Mathematics 2015-04-10 Teeradej Kittipassorn , Gabor Meszaros

A normal 5-edge-coloring of a cubic graph is a coloring such that for every edge the number of distinct colors incident to its end-vertices is 3 or 5 (and not 4). The well known Petersen Coloring Conjecture is equivalent to the statement…

Combinatorics · Mathematics 2023-12-18 Jelena Sedlar , Riste Škrekovski

In this paper, we are motivated by the conjectures proposed by C.~Bender \textit{et al.}, \cite{C} in 2024. We have settled the first two conjectures negatively by providing a counter example in \cite{KTJ}, whereas in this paper, we prove…

Combinatorics · Mathematics 2026-04-20 Anagha Khiste , Ganesh Tarte , Vinayak Joshi

The strong cycle double cover conjecture states that for every circuit $C$ of a bridgeless cubic graph $G$, there is a cycle double cover of $G$ which contains $C$. We conjecture that there is even a 5-cycle double cover $S$ of $G$ which…

Combinatorics · Mathematics 2012-11-12 Arthur Hoffmann-Ostenhof

Recent work showing the existence of conflict-free almost-perfect hypergraph matchings has found many applications. We show that, assuming certain simple degree and codegree conditions on the hypergraph $ \mathcal{H} $ and the conflicts to…

Combinatorics · Mathematics 2026-02-25 Felix Joos , Dhruv Mubayi , Zak Smith

In an edge-coloring of a cubic graph, an edge is poor or rich, if the set of colors assigned to the edge and the four edges adjacent it, has exactly five or exactly three distinct colors, respectively. An edge is normal in an edge-coloring…

Discrete Mathematics · Computer Science 2021-10-05 Giuseppe Mazzuoccolo , Vahan Mkrtchyan

We analyse a polyhedron which contains the convex hull of all Hamiltonian cycles of a given undirected connected cubic graph. Our constructed polyhedron is defined by polynomially-many linear constraints in polynomially-many continuous…

Combinatorics · Mathematics 2019-02-28 Jerzy A Filar , Michael Haythorpe , Serguei Rossomakhine

Contraction of triangles is a standard operation in the study of cubic graphs, as it reduces the order of the graph while typically preserving many of its properties. In this paper, we investigate the converse problem, wherein certain…

Combinatorics · Mathematics 2025-04-29 Giuseppe Mazzuoccolo , Vahan Mkrtchyan

We explore the well-known Jaeger's directed cycle double cover conjecture which is equivalent to the assertion that every cubic bridgeless graph has an embedding on a closed orientable surface with no dual loop. We associate each cubic…

Combinatorics · Mathematics 2013-10-22 Andrea Jiménez , Martin Loebl

The perfect matching complex of a simple graph $G$ is a simplicial complex having facets (maximal faces) as the perfect matchings of $G$. This article discusses the perfect matching complex of polygonal line tilings and the $\left(2 \times…

Combinatorics · Mathematics 2025-04-08 Himanshu Chandrakar , Anurag Singh

We present an algorithm for finding a perfect matching in a $3$-edge-connected cubic graph that intersects every $3$-edge cut in exactly one edge. Specifically, we propose an algorithm with a time complexity of $O(n \log^4 n)$, which…

Data Structures and Algorithms · Computer Science 2025-07-03 Babak Ghanbari , Robert Šámal