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The weak $r$-coloring numbers $wcol_r(G)$ of a graph $G$ were introduced by the first two authors as a generalization of the usual coloring number $col(G)$, and have since found interesting theoretical and algorithmic applications. This has…

Combinatorics · Mathematics 2020-02-11 H. A. Kierstead , Daqing Yang , Junjun Yi

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

Veit Elser proposed a random graph model for percolation in which physical dimension appears as a parameter. Studying this model combinatorially leads naturally to the consideration of numerical graph invariants which we call \emph{Elser…

The minimum positive $\ell$-degree $\delta^+_{\ell}(G)$ of a non-empty $k$-graph $G$ is the maximum $m$ such that every $\ell$-subset of $V(G)$ is contained in either none or at least $m$ edges of $G$; let $\delta^+_{\ell}(G):=0$ if $G$ has…

Combinatorics · Mathematics 2023-02-28 Oleg Pikhurko

Let $G$ be a finite group. A number of graphs with the vertex set $G$ have been studied, including the power graph, enhanced power graph, and commuting graph. These graphs form a hierarchy under the inclusion of edge sets, and it is useful…

Combinatorics · Mathematics 2021-12-07 G. Arunkumar , Peter J. Cameron , Rajat Kanti Nath , Lavanya Selvaganesh

Let $G$ be a group. The \emph{power graph} of $G$ is a graph with the vertex set $G$, having an edge between two elements whenever one is a power of the other. We characterize nilpotent groups whose power graphs have finite independence…

Combinatorics · Mathematics 2019-05-31 Ghodratollah Aalipour , Saieed Akbari , Peter J. Cameron , Reza Nikandish , Farzad Shaveisi

We introduce a new graph invariant that measures fractional covering of a graph by cuts. Besides being interesting in its own right, it is useful for study of homomorphisms and tension-continuous mappings. We study the relations with…

Combinatorics · Mathematics 2015-11-24 Robert Šámal

A fall $k$-coloring of a graph $G$ is a proper $k$-coloring of $G$ such that each vertex of $G$ sees all $k$ colors on its closed neighborhood. We denote ${\rm Fall}(G)$ the set of all positive integers $k$ for which $G$ has a fall…

Combinatorics · Mathematics 2009-09-16 Saeed Shaebani

Graph anomaly detection faces significant challenges due to the scarcity of reliable anomaly-labeled datasets, driving the development of unsupervised methods. Graph autoencoders (GAEs) have emerged as a dominant approach by reconstructing…

Machine Learning · Computer Science 2025-06-03 Chunyu Wei , Wenji Hu , Xingjia Hao , Yunhai Wang , Yueguo Chen , Bing Bai , Fei Wang

A $P_\ell$-decomposition of a graph $G$ is a set of paths with $\ell$ edges in $G$ that cover the edge set of $G$. Favaron, Genest, and Kouider (2010) conjectured that every $(2k+1)$-regular graph that contains a perfect matching admits a…

Combinatorics · Mathematics 2020-12-10 Fábio Botler , Luiz Hoffmann

Proper graph coloring assigns different colors to adjacent vertices of the graph. Usually, the number of colors is fixed or as small as possible. Consider applications (e.g. variants of scheduling) where colors represent limited resources…

Combinatorics · Mathematics 2019-09-10 Tomáš Masařík

Let $G$ be a simple graph with maximum degree $\Delta$. We call $G$ \emph{overfull} if $|E(G)|>\Delta \lfloor |V(G)|/2\rfloor$. The \emph{core} of $G$, denoted $G_{\Delta}$, is the subgraph of $G$ induced by its vertices of degree $\Delta$.…

Combinatorics · Mathematics 2020-04-03 Yan Cao , Guantao Chen , Guangming Jing , Songling Shan

A fractional colouring of a graph $G$ is a function that assigns a non-negative real value to all possible colour-classes of $G$ containing any vertex of $G$, such that the sum of these values is at least one for each vertex. The fractional…

Combinatorics · Mathematics 2022-12-27 John Baptist Gauci , Jean Paul Zerafa

Real-world graphs generally have only one kind of tendency in their connections. These connections are either homophily-prone or heterophily-prone. While graphs with homophily-prone edges tend to connect nodes with the same class (i.e.,…

Social and Information Networks · Computer Science 2023-06-14 Yizhen Zheng , He Zhang , Vincent CS Lee , Yu Zheng , Xiao Wang , Shirui Pan

Zero forcing is a graph coloring process that is used to model spreading phenomena in real-world scenarios. It can also be viewed as a single-player combinatorial game on a graph, where the player's goal is to select a subset of vertices of…

Combinatorics · Mathematics 2025-09-05 Aida Abiad , Maryam Moghaddas

A proper vertex coloring of a graph is equitable if the sizes of all color classes differ by at most $1$. For a list assignment $L$ of $k$ colors to each vertex of an $n$-vertex graph $G$, an equitable $L$-coloring of $G$ is a proper…

Combinatorics · Mathematics 2025-12-30 H. A. Kierstead , Alexandr Kostochka , Zimu Xiang

Fault-tolerant connectivity labelings are schemes that, given an $n$-vertex graph $G=(V,E)$ and $f\geq 1$, produce succinct yet informative labels for the elements of the graph. Given only the labels of two vertices $u,v$ and of the…

Data Structures and Algorithms · Computer Science 2024-02-20 Asaf Petruschka , Shay Sapir , Elad Tzalik

Motivated by the notion of chip-firing on the dual graph of a planar graph, we consider `integral flow chip-firing' on an arbitrary graph $G$. The chip-firing rule is governed by ${\mathcal L}^*(G)$, the dual Laplacian of $G$ determined by…

Combinatorics · Mathematics 2021-08-26 Anton Dochtermann , Eli Meyers , Raghav Samavedan , Alex Yi

Let G be a finite graph with the non-k-order property (essentially, a uniform finite bound on the size of an induced sub-half-graph). A major result of the paper applies model-theoretic arguments to obtain a stronger version of…

Logic · Mathematics 2015-08-20 M. Malliaris , S. Shelah

A totally silver coloring of a graph G is a k--coloring of G such that for every vertex v \in V(G), each color appears exactly once on N[v], the closed neighborhood of v. A totally silver graph is a graph which admits a totally silver…

Combinatorics · Mathematics 2013-02-14 M. Ghebleh , E. S. Mahmoodian