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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'

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

We provide precise asymptotic estimates for the number of several classes of labelled cubic planar graphs, and we analyze properties of such random graphs under the uniform distribution. This model was first analyzed by Bodirsky et al.…

Combinatorics · Mathematics 2019-07-26 Marc Noy , Clément Requilé , Juanjo Rué

Lovasz and Plummer conjectured that there exists a fixed positive constant c such that every cubic n-vertex graph with no cutedge has at least 2^(cn) perfect matchings. Their conjecture has been verified for bipartite graphs by Voorhoeve…

Combinatorics · Mathematics 2022-10-05 Sang-il Oum

We show that every cubic bridgeless graph G has at least 2^(|V(G)|/3656) perfect matchings. This confirms an old conjecture of Lovasz and Plummer. This version of the paper uses a different definition of a burl from the journal version of…

Combinatorics · Mathematics 2015-09-28 Louis Esperet , Frantisek Kardos , Andrew King , Daniel Kral , Serguei Norine

Let G be a bridgeless cubic graph. A well-known conjecture of Berge and Fulkerson can be stated as follows: there exist five perfect matchings of G such that each edge of G is contained in at least one of them. Here, we prove that in each…

Combinatorics · Mathematics 2013-06-06 Giuseppe Mazzuoccolo

In 1994, it was conjectured by Fan and Raspaud that every simple bridgeless cubic graph has three perfect matchings whose intersection is empty. In this paper we answer a question recently proposed by Mkrtchyan and Vardanyan, by giving an…

Combinatorics · Mathematics 2022-03-22 Giuseppe Mazzuoccolo , Jean Paul Zerafa

We show that every cubic bridgeless graph with n vertices has at least 3n/4-10 perfect matchings. This is the first bound that differs by more than a constant from the maximal dimension of the perfect matching polytope.

Combinatorics · Mathematics 2015-09-28 Louis Esperet , Daniel Kral , Petr Skoda , Riste Skrekovski

We introduce the matching measure of a finite graph as the uniform distribution on the roots of the matching polynomial of the graph. We analyze the asymptotic behavior of the matching measure for graph sequences with bounded degree. A…

Combinatorics · Mathematics 2021-08-31 Miklos Abért , Péter Csikvári , Péter Frenkel , Gábor Kun

If $G$ is a bridgeless cubic graph, Fulkerson conjectured that we can find 6 perfect matchings $M_1,...,M_6$ of $G$ with the property that every edge of $G$ is contained in exactly two of them and Berge conjectured that its edge set can be…

Discrete Mathematics · Computer Science 2009-04-09 Jean-Luc Fouquet , Jean-Marie Vanherpe

A conjecture of Berge and Fulkerson (1971) states that every cubic bridgeless graph contains 6 perfect matchings covering each edge precisely twice, which easily implies that every cubic bridgeless graph has three perfect matchings with…

Combinatorics · Mathematics 2015-04-17 Louis Esperet , Giuseppe Mazzuoccolo

We discuss the question whether the existence of perfect matchings in a cubic graph can be seen from the spectrum of its adjacency matrix. For regular graphs in general and for three edge-disjoint perfect matchings in a cubic graph (that…

Combinatorics · Mathematics 2026-01-08 Willem H. Haemers

The 1970s conjecture of Lov\'asz and Plummer that the number of perfect matchings in any $3$-regular graph is exponential in the number of vertices was proved in 2011 by Esperet, Kardo\v{s}, King, Kr\'al', and Norine. We give the exact…

Combinatorics · Mathematics 2020-03-26 R. S. Lekshmi , Douglas B. West

A conjecture of M\'a\u{c}ajov\'a and \u{S}koviera asserts that every bridgeless cubic graph has two perfect matchings whose intersection does not contain any odd edge cut. We prove this conjecture for graphs with few vertices and we give a…

Discrete Mathematics · Computer Science 2010-03-30 Jean-Luc Fouquet , Jean-Marie Vanherpe

A conjecture of Berge suggests that every bridgeless cubic graph can have its edges covered with at most five perfect matchings. Since three perfect matchings suffice only when the graph in question is $3$-edge-colourable, the rest of cubic…

Combinatorics · Mathematics 2020-08-05 Edita Máčajová , Martin Škoviera

A conjecture of Fan and Raspaud [3] asserts that every bridgeless cubic graph con-tains three perfect matchings with empty intersection. Kaiser and Raspaud [6] sug-gested a possible approach to this problem based on the concept of a…

Discrete Mathematics · Computer Science 2008-09-30 Jean-Luc Fouquet , Jean-Marie Vanherpe

It is proved that for $n \geq 6$, the number of perfect matchings in a simple connected cubic graph on $2n$ vertices is at most $4 f_{n-1}$, with $f_n$ being the $n$-th Fibonacci number. The unique extremal graph is characterized as well.…

Combinatorics · Mathematics 2024-04-01 Peter Horak , Dongryul Kim

We show that the ratio of the number of near perfect matchings to the number of perfect matchings in $d$-regular strong expander (non-bipartite) graphs, with $2n$ vertices, is a polynomial in $n$, thus the Jerrum and Sinclair Markov chain…

Data Structures and Algorithms · Computer Science 2021-03-17 Farzam Ebrahimnejad , Ansh Nagda , Shayan Oveis Gharan

Petersen's seminal work in 1891 asserts that the edge-set of a cubic graph can be covered by distinct perfect matchings if and only if it is bridgeless. Actually, it is known that for a very large fraction of bridgeless cubic graphs, every…

Combinatorics · Mathematics 2024-10-16 Jan Goedgebeur , Davide Mattiolo , Giuseppe Mazzuoccolo , Jarne Renders , Isaak H. Wolf

Perfect matchings and maximum weight matchings are two fundamental combinatorial structures. We consider the ratio between the maximum weight of a perfect matching and the maximum weight of a general matching. Motivated by the computer…

Discrete Mathematics · Computer Science 2018-11-08 Emilio Vital Brazil , Guilherme D. da Fonseca , Celina de Figueiredo , Diana Sasaki
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