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The \emph{matching preclusion number} of a graph is the minimum number of edges whose deletion results in a graph that has neither perfect matchings nor almost perfect matchings. As a generalization, Liu and Liu recently introduced the…

Combinatorics · Mathematics 2023-06-22 Tianlong Ma , Yaping Mao , Eddie Cheng , Christopher Melekian

We give an algorithm that finds a zero forcing set which approximates the optimal size by a factor of $\text{pw}(G)+1$, where $\text{pw}(G)$ is the pathwidth of $G$. Starting from a path decomposition, the algorithm runs in $O(nm)$ time,…

Combinatorics · Mathematics 2024-02-15 Ben Cameron , Jeannette Janssen , Rogers Matthew , Zhiyuan Zhang

In 2018, forts were defined as non-empty subsets of vertices in a graph where no vertex outside the set has exactly one neighbor in the set. Forts have since been used to characterize zero forcing sets, model zero forcing as an integer…

Combinatorics · Mathematics 2025-07-16 Boris Brimkov , Thomas R. Cameron , Owen Grubbs

Let $G=(V,E)$ be a simple graph. A dominating set of $G$ is a subset $S\subseteq V$ such that every vertex not in $S$ is adjacent to at least one vertex in $S$. The cardinality of a smallest dominating set of $G$, denoted by $\gamma(G)$, is…

Combinatorics · Mathematics 2022-11-15 Saieed Akbari , Nima Ghanbari , Michael A. Henning

The concept of zero forcing involves a dynamic coloring process by which blue vertices cause white vertices to become blue, with the goal of forcing the entire graph blue while choosing as few as possible vertices to be initially blue. Past…

Combinatorics · Mathematics 2024-09-10 Sara Anderton , Kanno Mizozoe , Houston Schuerger , Andrew Schwartz

We investigate families of graphs and graphons (graph limits) that are defined by a finite number of prescribed subgraph densities. Our main focus is the case when the family contains only one element, i.e., a unique structure is forced by…

Combinatorics · Mathematics 2013-08-23 Laszlo Lovasz , Balazs Szegedy

In this paper, we propose computational approaches for the zero forcing problem, the connected zero forcing problem, and the problem of forcing a graph within a specified number of timesteps. Our approaches are based on a combination of…

Discrete Mathematics · Computer Science 2018-09-20 Boris Brimkov , Caleb C. Fast , Illya V. Hicks

Zero forcing is a binary coloring game on a graph where a set of filled vertices can force non-filled vertices to become filled following a color change rule. In 2008, the zero forcing number of a graph was shown to be an upper bound on its…

Combinatorics · Mathematics 2025-08-12 Thomas R. Cameron , Jonad Pulaj

Zero forcing is an iterative graph coloring process studied for its wide array of applications. In this process, the vertices of the graph are initially designated as blue or white, and a zero forcing set is a set of initially blue vertices…

Combinatorics · Mathematics 2026-03-23 Asher Brown , Mark Hunnell , Za'Kiyah Toomer-Sanders , Sarah Weber

A graph in which all minimal zero forcing sets are in fact minimum size is called ``well-forced." This paper characterizes well-forced trees and presents an algorithm for determining which trees are well-forced. Additionally, we…

Combinatorics · Mathematics 2023-12-25 Cheryl Grood , Ruth Haas , Bonnie Jacob , Erika King , Shahla Nasserasr

Motivated by a conjecture from the automated conjecturing program TxGraffiti, in this paper the relationship between the zero forcing number, $Z(G)$, and the vertex independence number, $\alpha(G)$, of cubic and subcubic graphs is explored.…

Combinatorics · Mathematics 2024-11-04 Houston Schuerger , Nathan Warnberg , Michael Young

Given a graph $G$, a total dominating set $D_t$ is a vertex set that every vertex of $G$ is adjacent to some vertices of $D_t$ and let $d_t(G,i)$ be the number of all total dominating sets with size $i$. The total domination polynomial,…

Combinatorics · Mathematics 2016-07-05 Jiuhua Hu , Erfang Shan , Shaohui Wang , Chunxiang Wang , Bing Wei

A (simple) hypergraph is a family H of pairwise incomparable sets of a finite set. We say that a hypergraph H is a domination hypergraph if there is at least a graph G such that the collection of minimal dominating sets of G is equal to H.…

Combinatorics · Mathematics 2016-05-06 Jaume Martí-Farré , Mercè Mora , José Luis Ruiz

We provide a short proof of a conjecture of Davila and Kenter concerning a lower bound on the zero forcing number $Z(G)$ of a graph $G$. More specifically, we show that $Z(G)\geq (g-2)(\delta-2)+2$ for every graph $G$ of girth $g$ at least…

Combinatorics · Mathematics 2017-05-24 M. Fürst , D. Rautenbach

Let $G$ be a graph. A total dominating set of $G$ is a set $S$ of vertices of $G$ such that every vertex is adjacent to at least one vertex in $S$. The total domatic number of a graph is the maximum number of total dominating sets which…

Combinatorics · Mathematics 2015-12-16 Saieed Akbari , Mohammad Motiei , Sahand Mozaffari , Sina Yazdanbod

The \emph{fractional matching preclusion number} of a graph $G$, denoted by $fmp(G)$, is the minimum number of edges whose deletion results in a graph that has no fractional perfect matchings. In this paper, we first give some sharp upper…

Combinatorics · Mathematics 2019-09-18 Jinyu Zou , Yaping Mao , Zhao Wang , Eddie Cheng

The anti-forcing number of a connected graph $G$ is the smallest number of edges such that the remaining graph obtained by deleting these edges has a unique perfect matching. In this paper, we show that the anti-forcing number of every…

Combinatorics · Mathematics 2015-03-09 Qin Yang , Heping Zhang , Yuqing Lin

A set $C$ of vertices of a simple graph is called a completely regular code if for each $i=0$, $1$, $2$, \ldots and $j = i-1$, $i$, $i+1$, all vertices at distance $i$ from $C$ have the same number $s_{ij}$ of neighbors at distance $j$ from…

Metric Geometry · Mathematics 2016-12-06 Sergey V. Avgustinovich , Denis S. Krotov , Anastasia Yu. Vasil'eva

The zero forcing number is a graph invariant introduced to study the minimum rank of the graph. In 2008, Aazami proved the NP-hardness of computing the zero forcing number of a simple undirected graph. We complete this NP-hardness result by…

Discrete Mathematics · Computer Science 2015-06-09 Maguy Trefois , Jean-Charles Delvenne

Let $ G $ be a graph with the vertex set $ V(G) $ and $ S $ be a subset of $ V(G) $. Let $cl(S)$ be the set of vertices built from $S$, by iteratively applying the following propagation rule: if a vertex and all of its neighbors except one…

Combinatorics · Mathematics 2021-06-28 Najibeh Shahbaznejad , Adel P Kazemi , Ignacio M Pelayo
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