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In a zero forcing process, vertices of a graph are colored black and white initially, and if there exists a black vertex adjacent to exactly one white vertex, then the white vertex is forced to be black. A zero blocking set is an initial…

Combinatorics · Mathematics 2025-08-14 Hau-Yi Lin , Wu-Hsiung Lin , Gerard Jennhwa Chang

Given a graph $G$, the zero forcing number of $G$, $Z(G)$, is the smallest cardinality of any set $S$ of vertices on which repeated applications of the forcing rule results in all vertices being in $S$. The forcing rule is: if a vertex $v$…

Combinatorics · Mathematics 2022-09-21 Aidan Johnson , Andrew E. Vick , Darren A. Narayan

A forcing set for a perfect matching of a graph is defined as a subset of the edges of that perfect matching such that there exists a unique perfect matching containing it. A complete forcing set for a graph is a subset of its edges, such…

Combinatorics · Mathematics 2024-09-27 Javad B. Ebrahimi , Aref Nemayande , Elahe Tohidi

The zero forcing number and the positive zero forcing number of a graph are two graph parameters that arise from two types of graph colourings. The zero forcing number is an upper bound on the minimum number of induced paths in the graph,…

Combinatorics · Mathematics 2013-11-28 Fatemeh Alinaghipour Taklimi , Shaun Fallat , Karen Meagher

A dynamic coloring of the vertices of a graph $G$ starts with an initial subset $S$ of colored vertices, with all remaining vertices being non-colored. At each discrete time interval, a colored vertex with exactly one non-colored neighbor…

Combinatorics · Mathematics 2017-02-22 Randy Davila , Michael Henning

Given a simple undirected graph $G$ and a positive integer $k$, the $k$-forcing number of $G$, denoted $F_k(G)$, is the minimum number of vertices that need to be initially colored so that all vertices eventually become colored during the…

Combinatorics · Mathematics 2014-01-27 David Amos , Yair Caro , Randy Davila , Ryan Pepper

In zero forcing, the focus is typically on finding the minimum cardinality of any zero forcing set in the graph; however, the number of cardinalities between $0$ and the number of vertices in the graph for which there are both zero forcing…

Combinatorics · Mathematics 2023-09-13 Bonnie Jacob

The concept of zero forcing is extended from graphs to uniform hypergraphs in analogy with the way zero forcing was defined as an upper bound for the maximum nullity of the family of symmetric matrices whose nonzero pattern of entries is…

Combinatorics · Mathematics 2018-08-30 Leslie Hogben

A set $Z$ of vertices of a graph $G$ is a zero forcing set of $G$ if initially labeling all vertices in $Z$ with $1$ and all remaining vertices of $G$ with $0$, and then, iteratively and as long as possible, changing the label of some…

Combinatorics · Mathematics 2016-08-03 Michael Gentner , Dieter Rautenbach

Given a graph $G$, the zero-forcing number of $G$, $Z(G)$, is the smallest cardinality of any set $S$ of vertices on which repeated applications of the forcing rule results in all vertices being in $S$. The forcing rule is: if a vertex $v$…

Combinatorics · Mathematics 2021-10-19 Luis Gomez , Karla Rubi , Jorden Terrazas , Darren A. Narayan

The tight upper bound $\operatorname{pt}_+(G) \leq \left\lceil \frac{\left\vert \operatorname{V}(G) \right\vert - \operatorname{Z}_+(G)}{2} \right\rceil$ is established for the positive semidefinite propagation time of a graph in terms of…

Combinatorics · Mathematics 2021-11-25 Leslie Hogben , Mark Hunnell , Kevin Liu , Houston Schuerger , Ben Small , Yaqi Zhang

A dynamic coloring of the vertices of a graph $G$ starts with an initial subset $F$ of colored vertices, with all remaining vertices being non-colored. At each time step, a colored vertex with exactly one non-colored neighbor forces this…

Combinatorics · Mathematics 2019-03-21 Meysam Alishahi , Elahe Rezaei-Sani , Elahe Sharifi

Zero forcing is a process on a graph $G = (V,E)$ in which a set of initially colored vertices,$B_0(G) \subset V(G)$, can color their neighbors according to the color change rule. The color change rule states that if a vertex $v$ can color a…

Combinatorics · Mathematics 2024-11-06 Rebekah Herrman , Grace Wisdom

Product throttling answers the question of minimizing the product of the resources needed to accomplish a task, and the time in which it takes to accomplish the task. In product throttling for positive semidefinite zero forcing, task that…

Combinatorics · Mathematics 2022-07-07 Esther Conrad

Zero forcing and power domination are iterative processes on graphs where an initial set of vertices are observed, and additional vertices become observed based on some rules. In both cases, the goal is to eventually observe the entire…

Combinatorics · Mathematics 2017-03-02 Daniela Ferrero , Leslie Hogben , Franklin H. J. Kenter , Michael Young

A connected forcing set of a graph is a zero forcing set that induces a connected subgraph. In this paper, we introduce and study CF-dense graphs -- graphs in which every vertex belongs to some minimum connected forcing set. We identify…

Combinatorics · Mathematics 2025-07-16 Boris Brimkov , Randy Davila , Houston Schuerger

An $r$-fold analogue of the positive semidefinite zero forcing process that is carried out on the $r$-blowup of a graph is introduced and used to define the fractional positive semidefinite forcing number. Properties of the graph blowup…

Combinatorics · Mathematics 2016-08-23 Leslie Hogben , Kevin F. Palmowski , David E. Roberson , Michael Young

Let $D$ be a simple digraph (directed graph) with vertex set $V(D)$ and arc set $A(D)$ where $n=|V(D)|$, and each arc is an ordered pair of distinct vertices. If $(v,u) \in A(D)$, then $u$ is considered an \emph{out-neighbor} of $v$ in $D$.…

Combinatorics · Mathematics 2020-07-31 Alyssa Adams , Bonnie Jacob

Let $G$ be a graph that admits a perfect matching. A {\sf forcing set} for a perfect matching $M$ of $G$ is a subset $S$ of $M$, such that $S$ is contained in no other perfect matching of $G$. This notion originally arose in chemistry in…

Combinatorics · Mathematics 2009-03-17 Peyman Afshani , Hamed Hatami , Ebadollah S. Mahmoodian

Let $p \in \mathbb{N}$ and $q \in \mathbb{N} \cup \lbrace \infty \rbrace$. We study a dynamic coloring of the vertices of a graph $G$ that starts with an initial subset $S$ of blue vertices, with all remaining vertices colored white. If a…

Combinatorics · Mathematics 2025-09-03 Boštjan Brešar , Jaka Hedžet , Michael A. Henning