English
Related papers

Related papers: Independence Complexes of Hexagonal Grid Graphs

200 papers

An independent set $I$ in a graph $G$ is maximal if $I$ is not properly contained in any other independent set of $G$. The study of maximal independent sets (MIS's) in various graphs is well-established, often focusing upon enumeration of…

Combinatorics · Mathematics 2025-06-30 Levi Axelrod , Nathan Bickel , Anastasia Halfpap , Luke Hawranick , Alex Parker , Cole Swain

The $k$-cut complex was recently introduced by Bayer et al. as a generalization of earlier work of Fr{\"o}berg (1990) and Eagon and Reiner (1998), and was shown to be shellable for several classes of graphs. In this article, we prove that…

Combinatorics · Mathematics 2026-02-06 Himanshu Chandrakar

We study the independence complexes of families of well-covered circulant graphs discovered by Boros-Gurvich-Milani\v{c}, Brown-Hoshino, and Moussi. Because these graphs are well-covered, their independence complexes are pure simplicial…

Combinatorics · Mathematics 2015-05-13 Jonathan Earl , Kevin N. Vander Meulen , Adam Van Tuyl

The matching complex $\mathsf{M}(G)$ of a graph $G$ is a simplicial complex whose simplices are matchings in $G$. These complexes appear in various places and found applications in many areas of mathematics including computational geometry,…

Combinatorics · Mathematics 2026-04-24 Raju Kumar Gupta , Sourav Sarkar , Sagar S. Sawant , Samir Shukla

The independence equivalence class of a graph $G$ is the set of graphs that have the same independence polynomial as $G$. Beaton, Brown and Cameron (arXiv:1810.05317) found the independence equivalence classes of even cycles, and raised the…

Combinatorics · Mathematics 2022-08-16 Boon Leong Ng

An outerplanar graph is a planar graph that has a planar drawing with all vertices on the unbounded face. The matching complex of a graph is the simplicial complex whose faces are subsets of disjoint edges of the graph. In this paper we…

Combinatorics · Mathematics 2024-11-08 Margaret Bayer , Marija Jelić Milutinović , Julianne Vega

We prove that independence complex of a bipartite circle graph is homotopy equivalent to a wedge of spheres, resolving a conjecture posed by Przytycki and Silvero. As a corollary, we obtain that extreme Khovanov spectrum,…

Geometric Topology · Mathematics 2023-03-22 Apratim Chakraborty

Given finite simple graphs $G$ and $H$, the Hom complex $\mathrm{Hom}(G,H)$ is a polyhedral complex having the graph homomorphisms $G\to H$ as the vertices. We determine the homotopy type of each connected component of $\mathrm{Hom}(G,H)$…

Combinatorics · Mathematics 2025-09-16 Soichiro Fujii , Kei Kimura , Yuta Nozaki

In 2007, Arkin et al. initiated a systematic study of the complexity of the Hamiltonian cycle problem on square, triangular, or hexagonal grid graphs, restricted to polygonal, thin, superthin, degree-bounded, or solid grid graphs. They…

Computational Complexity · Computer Science 2017-07-03 Erik D. Demaine , Mikhail Rudoy

We generalize some homotopy calculation techniques such as splittings and matching trees that are introduced for the computations in the case of the independence complexes of graphs to arbitrary simplicial complexes, and exemplify their…

Combinatorics · Mathematics 2015-01-28 Demet Taylan

In this paper, we prove that for every connected graph G, there exists a split graph H with the same independence number and the same order. Then we propose a first algorithm for finding this graph, given the degree sequence of the input…

Discrete Mathematics · Computer Science 2008-01-09 Omar Kettani

A ternary graph is a graph with no induced cycles of length $0$ modulo $3$. It was recently shown that, if the independence complex of a ternary graph is not contractible, then it is homotopy equivalent to a sphere. When a ternary graph…

Combinatorics · Mathematics 2025-08-04 Taehyun Eom , Jinha Kim , Minki Kim

For $r\geq 1$, the $r$-matching complex of a graph $G$, denoted $M_r(G)$, is a simplicial complex whose faces are the subsets $H \subseteq E(G)$ of the edge set of $G$ such that the degree of any vertex in the induced subgraph $G[H]$ is at…

Combinatorics · Mathematics 2021-12-10 Anurag Singh

Inspired by work of Fr\"oberg (1990), and Eagon and Reiner (1998), we define the \emph{total $k$-cut complex} of a graph $G$ to be the simplicial complex whose facets are the complements of independent sets of size $k$ in $G$. We study the…

The Hom complex $\mathrm{Hom}(G, H)$ of graphs is a simplicial complex associated to a pair of graphs $G$ and $H$, and its homotopy type is of interest in the graph coloring problem and the homomorphism reconfiguration problem. In this…

Combinatorics · Mathematics 2026-02-04 Takahiro Matsushita

The independence polynomial of a graph is the generating polynomial for the number of independent sets of each size. Two graphs are said to be \textit{independence equivalent} if they have equivalent independence polynomials. We extend…

Combinatorics · Mathematics 2018-10-15 Iain Beaton , Jason I. Brown , Ben Cameron

$Hom(G,H)$ 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

A \v{C}ech complex of a finite simple graph $G$ is a nerve complex of balls in the graph, with one ball centered at each vertex. More precisely, let the \v{C}ech complex $\mathcal{N}(G,r)$ be the nerve of all closed balls of radius…

Combinatorics · Mathematics 2023-11-21 Henry Adams , Samir Shukla , Anurag Singh

Graph independence (also known as $\epsilon$-independence or $\lambda$-independence) is a mixture of classical independence and free independence corresponding to graph products or groups and operator algebras. Using conjugation by certain…

We consider a family of distance graphs in $\mathbb{R}^n$ and find its independent numbers in some cases. Define graph $J_{\pm}(n,k,t)$ in the following way: the vertex set consists of all vectors from $\{-1,0,1\}^n$ with $k$ nonzero…

Combinatorics · Mathematics 2022-10-06 Danila Cherkashin , Sergei Kiselev