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Related papers: On independence complexes of graph products

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Let $G=(V,E)$ be a graph and $n$ a positive integer. Let $I_n(G)$ be the abstract simplicial complex whose simplices are the subsets of $V$ that do not contain an independent set of size $n$ in $G$. We study the collapsibility numbers of…

Combinatorics · Mathematics 2024-10-15 Minki Kim , Alan Lew

The independence polynomial of a graph is the generating polynomial for the number of independent sets of each cardinality and its roots are called independence roots. We investigate here purely imaginary independence roots. We show that…

Combinatorics · Mathematics 2020-03-31 Ben Cameron , Jason I. Brown

The independence numbers of powers of graphs have been long studied, under several definitions of graph products, and in particular, under the strong graph product. We show that the series of independence numbers in strong powers of a fixed…

Information Theory · Computer Science 2016-11-17 Noga Alon , Eyal Lubetzky

We study the homotopy theory of diagrams of chain complexes over a field indexed by a finite poset, and show that it can be completely described in terms of appropriate diagrams of graded vector spaces.

Algebraic Topology · Mathematics 2024-04-05 David Blanc , Surojit Ghosh , Aziz Kharoof

Let G be a graph. The independence-domination number is the maximum over all independent sets I in G of the minimal number of vertices needed to dominate I. In this paper we investigate the computational complexity of independence…

Discrete Mathematics · Computer Science 2013-04-25 Wing-Kai Hon , Ton Kloks , Hsiang Hsuan Liu , Sheung-Hung Poon , Yue-Li Wang

We study the zero sets of the independence polynomial on recursive sequences of graphs. We prove that for a maximally independent starting graph and a stable and expanding recursion algorithm, the zeros of the independence polynomial are…

Dynamical Systems · Mathematics 2024-11-25 Mikhail Hlushchanka , Han Peters

The terms "whiskering", and more generally "grafting", refer to adding generators to any monomial ideal to make the resulting ideal Cohen-Macaulay. We investigate the independence complexes of simplicial complexes that are constructed…

Combinatorics · Mathematics 2025-03-25 Susan M. Cooper , Sara Faridi , Thiago Holleben , Lisa Nicklasson , Adam Van Tuyl

Recently there has been growing interest in discrete homotopies and homotopies of graphs beyond treating graphs as 1-dimensional simplicial spaces. One such type of homotopy is $\times$-homotopy. Recent work by Chih-Scull has developed a…

Combinatorics · Mathematics 2025-04-22 Keira Behal , Tien Chih

This article studies automorphism groups of graph products of arbitrary groups. We completely characterise automorphisms that preserve the set of conjugacy classes of vertex groups as those automorphisms that can be decomposed as a product…

Group Theory · Mathematics 2019-08-07 Anthony Genevois , Alexandre Martin

An independent dominating set of the simple graph $G=(V,E)$ is a vertex subset that is both dominating and independent in $G$. The independent domination polynomial of a graph $G$ is the polynomial $D_i(G,x)=\sum_{A} x^{|A|}$, summed over…

Combinatorics · Mathematics 2018-12-10 Somayeh Jahari , Saeid Alikhani

We introduce and study, for a process P delivering edges on the Cartesian product of the vertex sets of a given set of graphs, the P-product of these graphs, thereby generalizing many types of product graph. Analogous to the notion of a…

Combinatorics · Mathematics 2017-02-10 Izak Broere , Johannes Heidema

We study classes of countable graphs where every member does not contain a given finite graph as an induced subgraph -- denoted by $\mathsf{Free}(\mathcal{G})$ for a given finite graph $\mathcal{G}$. Our main results establish a structural…

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

Combinatorics · Mathematics 2020-01-22 Priyavrat Deshpande , Samir Shukla , Anurag Singh

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

We provide a recursive construction of an acyclic matching (also known as a gradient vector field, an equivalent notion to a discrete Morse function) on the independence complex of a graph with a simplicial vertex using given acyclic…

Combinatorics · Mathematics 2026-04-15 Sucharita Barik , Anupam Mondal , Sajal Mukherjee

In this paper we investigate the connectedness and the isomorphism problems for zig-zag products of two graphs. A sufficient condition for the zig-zag product of two graphs to be connected is provided, reducing to the study of the…

Combinatorics · Mathematics 2017-03-10 Daniele D'Angeli , Alfredo Donno , Ecaterina Sava-Huss

Recently, Zhang and Wu proved a conjecture of Kalai and Meshulam, showing that for every graph $G$ without induced cycles of length divisible by $3$, the sum of all reduced Betti numbers of its independence complex $I(G)$ is at most $1$. We…

Combinatorics · Mathematics 2025-12-29 Jinha Kim

In the Independent set problem, the input is a graph $G$, every vertex has a non-negative integer weight, and the task is to find a set $S$ of pairwise non-adjacent vertices, maximizing the total weight of the vertices in $S$. We give an…

Data Structures and Algorithms · Computer Science 2015-09-02 Daniel Lokshtanov , Marcin Pilipczuk , Erik Jan van Leeuwen

This paper investigates the shellability of $r$-independence complexes $\mathcal{I}_r(G)$, a generalization of classical independence complexes introduced by Paolini and Salvetti. For a graph $G$, a subset $A \subseteq V(G)$ is…

Combinatorics · Mathematics 2025-09-24 Arka Ghosh , S Selvaraja

The independence polynomial $I(G, x)$ of a graph $G$ is the polynomial in variable $x$ in which the coefficient $a_n$ on $x^n$ gives the number of independent subsets $S \subseteq V(G)$ of vertices of $G$ such that $|S| = n$. $I(G, x)$ is…

Combinatorics · Mathematics 2018-02-20 Patrick Bahls , Bailey Ethridge , Levente Szabo