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Related papers: 2-Matching Complexes

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We denote the matching complex of the complete graph with $n$ vertices by $M_n$. Bouc first studied the topological properties of $M_n$ in connection with the Quillen complex. Later Bj\"{o}rner, Lov\'{a}sz, Vre\'{c}ica, and…

Combinatorics · Mathematics 2024-01-18 Anupam Mondal , Sajal Mukherjee , Kuldeep Saha

An $r$-matching in a graph $G$ is a collection of edges in $G$ such that the distance between any two edges is at least $r$. A $2$-matching is also called an induced matching. In this paper, we estimate the maximum number of $r$-matchings…

Combinatorics · Mathematics 2014-11-18 Dong Yeap Kang , Jaehoon Kim , Younjin Kim , Hiu-Fai Law

We define the $k$-cut complex of a graph $G$ with vertex set $V(G)$ to be the simplicial complex whose facets are the complements of sets of size $k$ in $V(G)$ inducing disconnected subgraphs of $G$. This generalizes the Alexander dual of a…

The matching complex $M(G)$ of a simple graph $G$ is the simplicial complex consisting of the matchings on $G$. The matching complex $M(G)$ is isomorphic to the independence complex of the line graph $L(G)$. Braun and Hough introduced a…

Combinatorics · Mathematics 2019-07-01 Takahiro Matsushita

Topological data analysis can extract effective information from higher-dimensional data. Its mathematical basis is persistent homology. The persistent homology can calculate topological features at different spatiotemporal scales of the…

Algebraic Topology · Mathematics 2023-09-29 Dinghua Shi , Zhifeng Chen , Chuang Ma , Guanrong Chen

This is the second of a series of papers which are devoted to a comprehensive theory of maps between orbifolds. In this paper, we develop a basic machinery for studying homotopy classes of such maps. It contains two parts: (1) the…

Algebraic Topology · Mathematics 2007-05-23 Weimin Chen

For simple graphs $G$ and $H$, the Hom complex $\mathrm{Hom}(G,H)$ is a polyhedral complex whose vertices are the graph homomorphisms $G\to H$ and whose edges connect the pairs of homomorphisms which differ in a single vertex of $G$. Hom…

Combinatorics · Mathematics 2025-09-08 Soichiro Fujii , Yuni Iwamasa , Kei Kimura , Yuta Nozaki , Akira Suzuki

Given two discrete Morse functions on a simplicial complex, we introduce the {\em connectedness homomorphism} between the corresponding discrete Morse complexes. This concept leads to a novel framework for studying the connectedness in…

Combinatorics · Mathematics 2024-07-15 Chong Zheng

Various simplicial complexes can be associated with a graph. Box complexes form an important families of such simplicial complexes and are especially useful for providing lower bounds on the chromatic number of the graph via some of their…

Combinatorics · Mathematics 2024-01-05 Hamid Reza Daneshpajouh , Frédéric Meunier

A perfect matching in a hypergraph is a set of edges that partition the set of vertices. We study the complexity of deciding the existence of a perfect matching in orderable and separable hypergraphs. We show that the class of orderable…

Combinatorics · Mathematics 2022-02-03 Shmuel Onn

In this paper, we extend the definition of cohomology associated to monotone graph properties, to encompass twisted functor coefficients. We introduce oriented matchings on graphs, and focus on their (twisted) cohomology groups. We…

Combinatorics · Mathematics 2022-03-08 Luigi Caputi , Daniele Celoria , Carlo Collari

Homomorphically full graphs are those for which every homomorphic image is isomorphic to a subgraph. We extend the definition of homomorphically full to oriented graphs in two different ways. For the first of these, we show that…

Discrete Mathematics · Computer Science 2024-02-14 Thomas Bellitto , Christopher Duffy , Gary MacGillivray

The dual complex of a singularity is defined, up-to homotopy, using resolutions of singularities. In many cases, for instance for isolated singularities, we identify and study a "minimal" representative of the homotopy class that is well…

Algebraic Geometry · Mathematics 2014-03-18 Tommaso de Fernex , János Kollár , Chenyang Xu

A clique of a graph is a maximal set of vertices of size at least 2 that induces a complete graph. A $k$-clique-colouring of a graph is a colouring of the vertices with at most $k$ colours such that no clique is monochromatic. D\'efossez…

Computational Complexity · Computer Science 2013-12-12 Hélio B. Macêdo Filho , Raphael C. S. Machado , Celina M. H. de Figueiredo

The complement of the codimension 2 complex coordinate subspace arrangement is shown to be homotopy equivalent to a wedge of spheres.

Algebraic Topology · Mathematics 2007-05-23 Jelena Grbic , Stephen Theriault

In the branch of mathematics known as graph theory, graphs are considered as a set of points, called vertices, with connections between these points, called edges. The purpose of this paper is to study mappings between two graphs that have…

Combinatorics · Mathematics 2019-03-19 Jeffrey Beyerl , Cameron Sharpe

We present a mathematical framework for describing the topology of configuration spaces for particles on one-connected graphs. In particular, we compute the homology groups over integers for different classes of one-connected graphs. Our…

Mathematical Physics · Physics 2017-05-24 Tomasz Maciążek , Adam Sawicki

The recently introduced A-homotopy groups for graphs are investigated. The main concern of the present article is the construction of an infinite cell complex, the homotopy groups of which are isomorphic to the A-homotopy groups of the…

Combinatorics · Mathematics 2007-05-23 E. Babson , H. Barcelo , M. de Longueville , R. Laubenbacher

We study the perfect matching lattice of a matching covered graph $G$, generated by the incidence vectors of its perfect matchings. Building on results of Lov\'asz and de Carvalho, Lucchesi, and Murty, we give a polynomial-time algorithm…

Combinatorics · Mathematics 2025-11-07 Olha Silina

In this paper we present a new approach to computing homology (with field coefficients) and persistent homology. We use concepts from discrete Morse theory, to provide an algorithm which can be expressed solely in terms of simple graph…

Algebraic Topology · Mathematics 2012-10-26 Paweł Dłotko , Hubert Wagner