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The independence complex $\mathrm{Ind}(G)$ of a graph $G$ is the simplicial complex formed by its independent sets. This article introduces a deformation of the simplicial boundary map of $\mathrm{Ind}(G)$ that gives rise to a double…

Algebraic Topology · Mathematics 2020-10-01 Marko Berghoff

$Hom(G,H)$ is a polyhedral complex defined for any two undirected graphs $G$ and $H$. This construction was introduced by Lov\'asz to give lower bounds for chromatic numbers of graphs. In this paper we initiate the study of the topological…

Combinatorics · Mathematics 2007-05-23 Eric Babson , Dmitry N. Kozlov

For $r\geq 1$, the $r$-independence complex of a graph $G$ is a simplicial complex whose faces are subset $I \subseteq V(G)$ such that each component of the induced subgraph $G[I]$ has at most $r$ vertices. In this article, we determine the…

Algebraic Topology · Mathematics 2021-02-02 Priyavrat Deshpande , Anurag Singh

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 show that the category of N-complexes has a Str\om model structure, meaning the weak equivalences are the chain homotopy equivalences. This generalizes the analogous result for the category of chain complexes (N = 2). The trivial objects…

K-Theory and Homology · Mathematics 2012-07-31 James Gillespie

Let $P$ be a finite poset. We will show that for any reasonable $P$-persistent object $X$ in the category of finite topological spaces, there is a $P-$ weighted graph, whose clique complex has the same $P$-persistent homology as $X$.

Algebraic Topology · Mathematics 2015-02-18 Francesco Vaccarino , Alice Patania , Giovanni Petri

We show that the independence complexes of generalised Mycielskian of complete graphs are homotopy equivalent to a wedge sum of spheres, and determine the number of copies and the dimensions of these spheres. We also prove that the…

Combinatorics · Mathematics 2022-04-29 Shuchita Goyal , Samir Shukla , Anurag Singh

It was proven by Gonz\'alez-Meneses, Manch\'on and Silvero that the extreme Khovanov homology of a link diagram is isomorphic to the reduced (co)homology of the independence simplicial complex obtained from a bipartite circle graph…

Geometric Topology · Mathematics 2016-08-11 Jozef H. Przytycki , Marithania Silvero

Crossed complexes are shown to have an algebra sufficiently rich to model the geometric inductive definition of simplices, and so to give a purely algebraic proof of the Homotopy Addition Lemma (HAL) for the boundary of a simplex. This…

Algebraic Topology · Mathematics 2007-05-23 Ronald Brown , Rafael Sivera

Given two finite abstract simplicial complexes A and B, one can define a new simplicial complex on the set of simplicial maps from A to B. After adding two technicalities, we call this complex Homsc(A, B). We prove the following dichotomy:…

General Topology · Mathematics 2024-08-16 Sebastian Meyer

We demonstrate that the proper homotopy equivalence relation for locally finite graphs is Borel complete. Furthermore, among the infinite graphs, there is a comeager equivalence class. As corollaries, we obtain the analogous results for the…

Logic · Mathematics 2025-11-13 Hannah Hoganson , Jenna Zomback

Graph classification plays an important role is data mining, and various methods have been developed recently for classifying graphs. In this paper, we propose a novel method for graph classification that is based on homotopy equivalence of…

Discrete Mathematics · Computer Science 2017-07-18 Alexander V. Evako

Let p be a fibration over a finite simplicial complex, whose fibers have the homotopy type of finite simplicial complexes. Then p is equivalent to an approximate fibration whose total space is a compact ENR. The proof uses homotopy coherent…

Algebraic Topology · Mathematics 2011-09-29 Wolfgang Steimle

Hypergraph is a topological model for networks. In order to study the topology of hypergraphs, the homology of the associated simplicial complexes and the embedded homology have been invented. In this paper, we give some algorithms to…

Algebraic Topology · Mathematics 2018-01-03 Shiquan Ren , Chengyuan Wu , Stephane Bressan , Jie Wu

Correspondence homomorphisms are both a generalization of standard homomorphisms and a generalization of correspondence colourings. For a fixed target graph $H$, the problem is to decide whether an input graph $G$, with each edge labeled by…

Discrete Mathematics · Computer Science 2018-03-30 Tomas Feder , Pavol Hell

In this paper we study the homotopy type of $\Hom(C_m,C_n)$, where $C_k$ is the cyclic graph with $k$ vertices. We enumerate connected components of $\Hom(C_m,C_n)$ and show that each such component is either homeomorphic to a point or…

Combinatorics · Mathematics 2007-05-23 Sonja Lj. Cukic , Dmitry N. Kozlov

A matching complex of a simple graph $G$ is a simplicial complex with faces given by the matchings of $G$. The topology of matching complexes is mysterious; there are few graphs for which the homotopy type is known. Marietti and Testa…

Combinatorics · Mathematics 2021-02-01 Marija Jelić Milutinović , Helen Jenne , Alex McDonough , Julianne Vega

We consider simplicial complexes that are generated from the binomial random 3-uniform hypergraph by taking the downward-closure. We determine when this simplicial complex is homologically connected, meaning that its zero-th and first…

Combinatorics · Mathematics 2016-04-05 Oliver Cooley , Penny Haxell , Mihyun Kang , Philipp Sprüssel

A map $f:X\to Y$ to a simplicial complex $Y$ is called a $Y$-triangular homotopy equivalence if it has a homotopy inverse $g$ and homotopies $h_1:f\circ g\simeq \mathrm{id}_Y$, $h_2:g\circ f\simeq \mathrm{id}_X$ such that for all simplices…

Algebraic Topology · Mathematics 2013-11-15 Spiros Adams-Florou

We prove that every finite connected simplicial complex has the homology of the classifying space for some $\mathrm{CAT}(0)$ cubical duality group. More specifically, for any finite simplicial complex $X$, we construct a locally…

Metric Geometry · Mathematics 2012-12-11 Raeyong Kim