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Related papers: A zero-sum problem on graphs

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We investigate the zero-forcing number for triangle-free graphs. We improve upon the trivial bound, $\delta \le Z(G)$ where $\delta$ is the minimum degree, in the triangle-free case. In particular, we show that $2 \delta - 2 \le Z(G)$ for…

Combinatorics · Mathematics 2014-06-13 Randy Davila , Franklin Kenter

The power graph $\mathcal{P}(G)$ of a finite group $G$ is a graph whose vertex set is the group $G$ and distinct elements $x,y\in G$ are adjacent if one is a power of the other, that is, $x$ and $y$ are adjacent if $x\in\langle y\rangle$ or…

Let each vertex of a graph G = (V(G), E(G)) be given one of two colors, say, "black" and "white". Let Z denote the (initial) set of black vertices of G. The color-change rule converts the color of a vertex from white to black if the white…

Combinatorics · Mathematics 2015-03-19 Kiran B. Chilakamarri , Nathaniel Dean , Cong X. Kang , Eunjeong Yi

Given a graph $G$, one may ask: "What sets of eigenvalues are possible over all weighted adjacency matrices of $G$?" (The weight of an edge is positive or negative, while the diagonal entries can be any real numbers.) This is known as the…

Combinatorics · Mathematics 2021-04-14 Franklin H. j. Kenter , Jephian C. -H. Lin

Zero forcing is a combinatorial game played on a graph with a goal of turning all of the vertices of the graph black while having to use as few "unforced" moves as possible. This leads to a parameter known as the zero forcing number which…

Combinatorics · Mathematics 2012-11-21 Steve Butler , Jason Grout , H. Tracy Hall

The anti-forcing number of a perfect matching $M$ of a graph $G$ is the minimal number of edges not in $M$ whose removal to make $M$ as a unique perfect matching of the resulting graph. The set of anti-forcing numbers of all perfect…

Combinatorics · Mathematics 2016-07-20 Kai Deng , Heping 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

It is well-known that the zero forcing number of a graph provides a lower bound on the minimum rank of a graph. In this paper we bound and characterize the zero forcing number of certain circulant graphs, including some bipartite…

Combinatorics · Mathematics 2019-06-10 Linh Duong , Brenda K. Kroschel , Michael Riddell , Kevin N. Vander Meulen , Adam Van Tuyl

The global forcing number of a graph G is the minimal cardinality of an edge subset discriminating all perfect matchings of G, denoted by gf(G). For any perfect matching M of G, the minimal cardinality of an edge subset S in E(G)-M such…

Combinatorics · Mathematics 2022-11-08 Yaxian Zhang , Heping Zhang

This paper proves a conjecture generated by the artificial intelligence conjecturing program called \emph{TxGraffiti}. More specifically, we show that if $G$ is a connected, cubic, and claw-free graph, then $Z(G) \le \gamma(G) + 2$, where…

Combinatorics · Mathematics 2024-11-20 Randy R. Davila

For a finite group $G$, the vertices of the prime graph $\Gamma(G)$ are the primes that divide $|G|$, and two vertices $p$ and $q$ are connected by an edge if and only if there is an element of order $pq$ in $G$. Prime graphs of solvable…

Group Theory · Mathematics 2024-07-10 Thomas Michael Keller , Gavin Pettigrew , Saskia Solotko , Lixin Zheng

In this paper, controllability of systems defined on graphs is discussed. We consider the problem of controllability of the network for a family of matrices carrying the structure of an underlying directed graph. A one-to-one correspondence…

Systems and Control · Computer Science 2014-03-20 Nima Monshizadeh , Shuo Zhang , Kanat Camlibel

We associate a graph $\Gamma_G$ to a non locally cyclic group $G$ (called the non-cyclic graph of $G$) as follows: take $G\backslash Cyc(G)$ as vertex set, where $Cyc(G)=\{x\in G | \left<x,y\right> \text{is cyclic for all} y\in G\}$, and…

Group Theory · Mathematics 2007-08-20 Alireza Abdollahi , A. Mohammadi Hassanabadi

Given a graph $G$ and a real number $0\le p\le 1$, we define the random set $B_p(G)\subset V(G)$ by including each vertex independently and with probability $p$. We investigate the probability that the random set $B_p(G)$ is a zero forcing…

Combinatorics · Mathematics 2022-08-30 Bryan Curtis , Luyining Gan , Jamie Haddock , Rachel Lawrence , Sam Spiro

A mapping $l : E(G) \rightarrow A$, where $A$ is an abelian group which written additively, is called a labeling of the graph $G$. For every positive integer $h \geqslant 2$, a graph $G$ is said to be zero-sum $h$-magic if there is an edge…

Combinatorics · Mathematics 2020-10-13 Haobai Wang

We prove that the \emph{standard zero forcing number} $Z(G)$ and the \emph{positive semidefinite zero forcing number} $Z_+(G)$ are equal for all claw-free graphs $G$. This result resolves a conjecture proposed by the computer program…

Combinatorics · Mathematics 2024-12-19 Randy Davila , Houston Schuerger , Ben Small

For a group $G,$ let $\Gamma(G)$ denote the graph defined on the elements of $G$ in such a way that two distinct vertices are connected by an edge if and only if they generate $G$. Moreover let $\Gamma^*(G)$ be the subgraph of $\Gamma(G)$…

Group Theory · Mathematics 2018-10-09 Cristina Acciarri , Andrea Lucchini

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

A dominating set $D_{f}\subseteq V(G)$ of vertices in a graph $G$ is called a \emph{dom-forcing set} if the sub-graph induced by $\langle D_{f} \rangle$ must form a zero forcing set. The minimum cardinality of such a set is known as the…

Combinatorics · Mathematics 2024-11-04 Susanth P , Charles Dominic , Premodkumar K P

Chung, Graham and Wilson defined a set of graphs $\mathcal{H}$ to be forcing, if any sequence of graphs $\{G_n\}_{n \geq 0}$ with $|G_n| = n$ must be quasirandom, whenever $hom(H, G_n)= (p^{|E(H)|}+o(1))n^{|V(H)|}$ for every $H \in…

Combinatorics · Mathematics 2023-12-12 Nikola Spasić