English
Related papers

Related papers: Generating Near-Bipartite Bricks

200 papers

A brick is a $3$-connected graph such that the graph obtained from it by deleting any two distinct vertices has a perfect matching. A brick $G$ is near-bipartite if it has a pair of edges $\alpha$ and $\beta$ such that $G-\{\alpha,\beta\}$…

Combinatorics · Mathematics 2026-05-22 Nishad Kothari , Marcelo H. de Carvalho

An edge $e$ of a matching covered graph $G$ is removable if $G-e$ is also matching covered. The notion of removable edge arises in connection with ear decompositions of matching covered graphs introduced by Lov\'asz and Plummer. A…

Combinatorics · Mathematics 2024-06-04 Yipei Zhang , Fuliang Lu , Xiumei Wang , Jinjiang Yuan

A {\em brick} is a non-bipartite matching covered graph without non-trivial tight cuts. Bricks are building blocks of matching covered graphs. We say that an edge $e$ in a brick $G$ is {\em $b$-invariant} if $G-e$ is matching covered and a…

Combinatorics · Mathematics 2020-02-14 Fuliang Lu , Xing Feng , Yan Wang

Lov\'asz (1987) proved that every matching covered graph $G$ may be uniquely decomposed into a list of bricks (nonbipartite) and braces (bipartite); we let $b(G)$ denote the number of bricks. An edge $e$ is removable if $G-e$ is also…

Combinatorics · Mathematics 2026-05-22 Nishad Kothari , Marcelo H. de Carvalho , Cláudio L. Lucchesi , Charles H. C. Little

A connected graph G with at least two vertices is matching covered if each of its edges lies in a perfect matching. We say that an edge e in a matching covered graph G is removable if G-e is matching covered. A pair {e; f} of edges of a…

Combinatorics · Mathematics 2025-06-03 Xiaoling He , Fuliang Lu , Jinxin Xue

{ An edge $e$ in a matching covered graph $G$ is {\em removable} if $G-e$ is matching covered, which was introduced by Lov\'asz and Plummer in connection with ear decompositions of matching covered graphs. A {\it brick}} is a non-bipartite…

Combinatorics · Mathematics 2024-01-17 Lu Fuliang , Qian Jianguo

A brick is a 3-connected graph such that the graph obtained from it by deleting any two distinct vertices has a perfect matching. A brick is minimal if for every edge e the deletion of e results in a graph that is not a brick. We prove a…

Combinatorics · Mathematics 2019-07-02 Serguei Norine , Robin Thomas

A cut $C:=\partial(X)$ of a matching covered graph $G$ is a separating cut if both its $C$-contractions $G/X$ and $G/\overline{X}$ are also matching covered. A brick is solid if it is free of nontrivial separating cuts. In 2004, we…

Combinatorics · Mathematics 2026-05-21 Cláudio L. Lucchesi , Marcelo H. de Carvalho , Nishad Kothari , U. S. R. Murty

A connected graph G is matching covered if every edge lies in some perfect matching of G. Lovasz proved that every matching covered graph G can be uniquely decomposed into a list of bricks (nonbipartite) and braces (bipartite) up to…

Combinatorics · Mathematics 2024-11-27 Yaxian Zhang , Fuliang Lu , Heping Zhang

A graph $G$ is a brick if it is 3-connected and $G-\{u,v\}$ has a perfect matching for any two distinct vertices $u$ and $v$ of $G$. A brick $G$ is solid if for any two vertex disjoint odd cycles $C_1$ and $C_2$ of $G$, $G-(V(C_1)\cup…

Combinatorics · Mathematics 2025-07-30 Yipei Zhang , Xiumei Wang

An edge $e$ of a matching covered graph $G$ is removable if $G-e$ is also matching covered. Carvalho, Lucchesi, and Murty showed that every brick $G$ different from $K_4$ and $\overline{C_6}$ has at least $\Delta-2$ removable edges, where…

Combinatorics · Mathematics 2024-08-07 Deyu Wu , Yipei Zhang , Xiumei Wang

A subgraph $G'$ of a graph $G$ is nice if $G-V(G')$ has a perfect matching. Nice subgraphs play a vital role in the theory of ear decomposition and matching minors of matching covered graphs. A vertex $u$ of a cubic graph is nice if $u$ and…

Combinatorics · Mathematics 2025-09-01 Wuxian Chen , Fuliang Lu , Heping Zhang

A connected graph $G$, of order two or more, is matching covered if each edge lies in some \pema. The tight cut decomposition of a matching covered graph $G$ yields a list of bricks and braces; as per a theorem of Lov{\'a}sz~\cite{lova87},…

Combinatorics · Mathematics 2019-12-18 Fuliang Lu , Nishad Kothari , Xing Feng , Lianzhu Zhang

An edge e in a matching covered graph G is removable if G-e is matching covered; a pair {e; f} of edges of G is a removable doubleton if G-e-f is matching covered, but neither G-e nor G-f is. Removable edges and removable doubletons are…

Combinatorics · Mathematics 2024-10-29 Fuliang Lu , Jinxin Xue

A multigraph $G$ is near-bipartite if $V(G)$ can be partitioned as $I,F$ such that $I$ is an independent set and $F$ induces a forest. We prove that a multigraph $G$ is near-bipartite when $3|W|-2|E(G[W])|\ge -1$ for every $W\subseteq…

Combinatorics · Mathematics 2021-10-06 Daniel W. Cranston , Matthew P. Yancey

We study edge-decompositions of highly connected graphs into copies of a given tree. In particular we attack the following conjecture by Bar\'at and Thomassen: for each tree $T$, there exists a natural number $k_T$ such that if $G$ is a…

Combinatorics · Mathematics 2012-03-09 János Barát , Dániel Gerbner

A complete graph is the graph in which every two vertices are adjacent. For a graph $G=(V,E)$, the complete width of $G$ is the minimum $k$ such that there exist $k$ independent sets $\mathtt{N}_i\subseteq V$, $1\le i\le k$, such that the…

Discrete Mathematics · Computer Science 2016-12-28 Van Bang Le , Sheng-Lung Peng

A k-tree is either a complete graph on (k+1) vertices or given a k-tree G' with n vertices, a k-tree G with (n+1) vertices can be constructed by introducing a new vertex v and picking a k-clique Q in G' and then joining each vertex u in Q.…

Discrete Mathematics · Computer Science 2011-03-25 Suresh Badarla , R Rama

Suppose a finite, unweighted, combinatorial graph $G = (V,E)$ is the union of several (degree-)regular graphs which are then additionally connected with a few additional edges. $G$ will then have only a small number of vertices $v \in V$…

Combinatorics · Mathematics 2023-10-25 Tony Zeng

A graph $G$ is a brick if it is 3-connected and $G-\{u,v\}$ has a perfect matching for any two distinct vertices $u$ and $v$ of $G$. Lucchesi and Murty proposed a problem concerning the characterization of bricks, distinct from $K_4$,…

Combinatorics · Mathematics 2025-09-30 Yipei Zhang , Xiumei Wang
‹ Prev 1 2 3 10 Next ›