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Related papers: Bipartite Graft I: Dulmage-Mendelsohn Decompositio…

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We provide a canonical decomposition for a class of bipartite grafts known as combs. As every bipartite graft is a recursive combination of combs, our results provides a canonical decomposition for general bipartite grafts. Our new…

Combinatorics · Mathematics 2021-01-20 Nanao Kita

Factor-critical graphs are a classical concept in matching theory that constitute an important component of the Gallai-Edmonds canonical decomposition and Edmonds' algorithm for maximum matchings. Lov\'asz provided a constructive…

Combinatorics · Mathematics 2024-02-09 Nanao Kita

We establish the theory of the Dulmage-Mendelsohn decomposition for $b$-matchings. The original Dulmage-Mendelsohn decomposition is a classical canonical decomposition of bipartite graphs, which describes the structures of the maximum…

Combinatorics · Mathematics 2016-06-28 Nanao Kita

In matching theory, one of the most fundamental and classical branches of combinatorics, {\em canonical decompositions} of graphs are powerful and versatile tools that form the basis of this theory. However, the abilities of the known…

Combinatorics · Mathematics 2017-08-04 Nanao Kita

The Dulmage-Mendelsohn decomposition is a classical canonical decomposition in matching theory applicable for bipartite graphs, and is famous not only for its application in the field of matrix computation, but also for providing a…

Combinatorics · Mathematics 2017-08-03 Nanao Kita

This paper is a sequel of our previous paper (N. Kita: Bipartite graft {II}: Cathedral decomposition for combs. arXiv preprint arXiv:2101.06678, 2021). In our previous paper, a graft analogue of the Dulmage-Mendelsohn decomposition has been…

Combinatorics · Mathematics 2021-08-03 Nanao Kita

This paper is the first from a series of papers that establish a generalization of the basilica decomposition for cardinality minimum joins in grafts. Joins in grafts are also known as $T$-joins in graphs, where $T$ is a given set of…

Combinatorics · Mathematics 2017-12-07 Nanao Kita

The Dulmage--Mendelsohn decomposition (or the DM-decomposition) gives a unique partition of the vertex set of a bipartite graph reflecting the structure of all the maximum matchings therein. A bipartite graph is said to be DM-irreducible if…

Discrete Mathematics · Computer Science 2018-01-16 Kristóf Bérczi , Satoru Iwata , Jun Kato , Yutaro Yamaguchi

This paper is the second in a series of papers characterizing the maximum packing of \( T \)-cuts in bipartite grafts, following the first paper (N.~Kita, ``Tight cuts in bipartite grafts~I: Capital distance components,''…

Combinatorics · Mathematics 2025-04-01 Nanao Kita

This paper is concerned with structures of general graphs with perfect matchings. We first reveal a partially ordered structure among factor-components of general graphs with perfect matchings. Our second result is a generalization of…

Discrete Mathematics · Computer Science 2013-03-26 Nanao Kita

A decomposition of a graph is a set of subgraphs whose edges partition those of $G$. The 3-decomposition conjecture posed by Hoffmann-Ostenhof in 2011 states that every connected cubic graph can be decomposed into a spanning tree, a…

Combinatorics · Mathematics 2022-11-08 Oliver Bachtler , Sven O. Krumke

This paper is the first from a series of papers that provide a characterization of maximum packings of $T$-cuts in bipartite graphs. Given a connected graph, a set $T$ of an even number of vertices, and a minimum $T$-join, an edge weighting…

Combinatorics · Mathematics 2022-02-21 Nanao Kita

We show that each perfect matching in a bipartite graph $G$ intersects at least half of the perfect matchings in $G$. This result has equivalent formulations in terms of the permanent of the adjacency matrix of a graph, and in terms of…

Combinatorics · Mathematics 2019-10-14 Matija Bucic , Pat Devlin , Mo Hendon , Dru Horne , Ben Lund

A connected graph, on four or more vertices, is matching covered (aka 1-extendable) if every edge is present in some perfect matching. An ear decomposition theorem exists for bipartite matching covered graphs due to Hetyei. From the results…

Combinatorics · Mathematics 2026-05-21 Amit Kumar Mallik , Ajit A. Diwan , Nishad Kothari

A matching $M$ in a graph $\Gamma$ is positive if $\Gamma$ has a vertex-labeling such that $M$ coincides with the set of edges with positive weights. A positive matching decomposition (pmd) of $\Gamma$ is an edge-partition $M_1,\ldots,M_p$…

In a sequence of four papers, we prove the following results (via a unified approach) for all sufficiently large $n$: (i) [1-factorization conjecture] Suppose that $n$ is even and $D \geq 2\lceil n/4\rceil -1$. Then every $D$-regular graph…

Combinatorics · Mathematics 2014-10-24 Béla Csaba , Daniela Kühn , Allan Lo , Deryk Osthus , Andrew Treglown

Intuitively speaking, a bipartite graph is mirror if it can be drawn in the Cartesian plane in such a way that, the vertices of one stable are points in x=0, the vertices of the other stable set are points in x=1, the edges are straight…

Combinatorics · Mathematics 2013-12-13 Susana-Clara López , Francesc-Antoni Muntaner-Batle

This paper is the first from a series of papers that establish a common analogue of the strong component and basilica decompositions for bidirected graphs. A bidirected graph is a graph in which a sign $+$ or $-$ is assigned to each end of…

Combinatorics · Mathematics 2017-09-22 Nanao Kita

Let $G$ be a simple graph with order $n$ and adjacency matrix $\mathbf{A}(G)$. Let $\phi(G; \lambda)=\det(\lambda I-\mathbf{A}(G))=\sum_{i=0}^n\mathbf{a}_i(G)\lambda^{n-i}$ be the characteristic polynomial of $G$, where $\mathbf{a}_i(G)$ is…

Combinatorics · Mathematics 2020-02-11 Shi Cai Gong , Shao Wei Sun

A distributive lattice structure ${\mathbf M}(G)$ has been established on the set of perfect matchings of a plane bipartite graph $G$. We call a lattice {\em matchable distributive lattice} (simply MDL) if it is isomorphic to such a…

Combinatorics · Mathematics 2015-03-09 Heping Zhang , Dewu Yang , Haiyuan Yao
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