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Let $G$ be a graph embedded on a surface $S_\varepsilon$ with Euler genus $\varepsilon > 0$, and let $P\subseteq V(G)$ be a set of vertices mutually at distance at least 4 apart. Suppose all vertices of $G$ have $H(\varepsilon)$-lists and…

组合数学 · 数学 2013-01-03 Alice M. Dean , Joan P. Hutchinson

Amos et al. (Discrete Appl. Math. 181 (2015) 1-10) introduced the notion of the $k$-forcing number of graph for a positive integer $k$ as the generalization of the zero forcing number of a graph. The $k$-forcing number of a simple graph…

组合数学 · 数学 2015-07-07 Leihao Lu , Baoyindureng Wu , Zixing Tang

We answer positively the question of Albertson asking whether every planar graph can be $5$-list-colored even if it contains precolored vertices, as long as they are sufficiently far apart from each other. In order to prove this claim, we…

组合数学 · 数学 2016-12-16 Zdenek Dvorak , Bernard Lidicky , Bojan Mohar , Luke Postle

For a graph $G = (V(G), E(G))$, a dominating set $D$ is a vertex subset of $V(G)$ in which every vertex of $V(G) \setminus D$ is adjacent to a vertex in $D$. The domination number of $G$ is the minimum cardinality of a dominating set of $G$…

组合数学 · 数学 2022-08-16 David A. Kalarkop , Pawaton Kaemawichanurat , Raghavachar Rangarajan

Bernshteyn and Lee defined a new notion, weak degeneracy, which is slightly weaker than the ordinary degeneracy. It is proved that strictly $f$-degenerate transversal is a common generalization of list coloring, $L$-forested-coloring and…

组合数学 · 数学 2022-07-05 Qianqian Wang , Tao Wang , Xiaojing Yang

A strong edge coloring of a graph $G$ is an edge coloring $\phi\,:\,E(G) \rightarrow \mathbb N$ such that each color class forms an induced matching in $G$. The strong chromatic index of $G$, written $\chi'_s(G)$, is the minimum number of…

组合数学 · 数学 2026-03-17 Richard Bi , Peter Bradshaw , Abhishek Dhawan , Jingwei Xu

We study choosability with separation which is a constrained version of list coloring of graphs. A (k,d)-list assignment L on a graph G is a function that assigns to each vertex v a list L(v) of at least k colors and for any adjacent pair…

组合数学 · 数学 2016-12-16 Ilkyoo Choi , Bernard Lidický , Derrick Stolee

A linear coloring of a graph is a proper coloring of the vertices of the graph so that each pair of color classes induce a union of disjoint paths. In this paper, we prove that for every connected graph with maximum degree at most three and…

组合数学 · 数学 2022-12-06 Chun-Hung Liu , Gexin Yu

We prove that for any graph $G$, the total chromatic number of $G$ is at most $\Delta(G)+2\left\lceil \frac{|V(G)|}{\Delta(G)+1} \right\rceil$. This saves one color in comparison with a result of Hind from 1992. In particular, our result…

组合数学 · 数学 2024-05-14 Aseem Dalal , Jessica McDonald , Songling Shan

Kostochka and Woodall (2001) conjectured that the square of every graph has the same chromatic number and list chromatic number. In 2015 Kim and Park disproved this conjecture for non-bipartite and bipartite graphs. It was asked by several…

组合数学 · 数学 2025-05-14 Morteza Hasanvand

Let $G = (V,E)$ be a graph, and for each $e \in E(G)$, let $L_e$ be a list of real numbers. Let $w:E(G) \to \cup_{e \in E(G)}L_e$ be an edge weighting function such that $w(e) \in L_e$ for each $e \in E(G)$, and let $c_w$ be the vertex…

组合数学 · 数学 2014-01-28 Ben Seamone

A proper coloring $\phi$ of $G$ is called a proper conflict-free coloring of $G$ if for every non-isolated vertex $v$ of $G$, there is a color $c$ such that $|\phi^{-1}(c)\cap N_G(v)|=1$. As an analogy to degree-choosability of graphs, the…

组合数学 · 数学 2025-09-09 Masaki Kashima , Riste Škrekovski , Rongxing Xu

It is proved that for every $\varepsilon>0$, there exists $K>0$ such that for every integer $t\ge2$, every graph with chromatic number at least $Kt$ contains a minor with $t$ vertices and edge density at least $1-\varepsilon$. Indeed,…

组合数学 · 数学 2022-08-09 Tung H. Nguyen

In 2003 Kostochka, Pelsmajer, and West introduced a list analogue of equitable coloring called equitable choosability. A $k$-assignment, $L$, for a graph $G$ assigns a list, $L(v)$, of $k$ available colors to each $v \in V(G)$, and an…

组合数学 · 数学 2019-08-06 Jeffrey A. Mudrock , Max Marsh , Tim Wagstrom

Zero forcing is a one-player game played on a graph. The player chooses some set of vertices to color, then iteratively applies a color change rule: If all but one of a colored vertex's neighbors are colored, color (i.e. "force") the…

组合数学 · 数学 2019-10-02 Shannon Dillman , Franklin Kenter

It is known that DP-coloring is a generalization of a list coloring in simple graphs and many results in list coloring can be generalized in those of DP-coloring. In this work, we introduce a relaxed DP-coloring which is a generalization if…

组合数学 · 数学 2018-03-12 Pongpat Sittitrai , Kittikorn Nakprasit

We study Koebe orderings of planar graphs: vertex orderings obtained by modelling the graph as the intersection graph of pairwise internally-disjoint discs in the plane, and ordering the vertices by non-increasing radii of the associated…

组合数学 · 数学 2022-01-25 Jesper Nederlof , Michał Pilipczuk , Karol Węgrzycki

A graph is 1-planar if it can be drawn on a plane so that each edge is crossed by at most one other edge. In this paper, we first give a useful structural theorem for 1-planar graphs, and then apply it to the list edge and list total…

组合数学 · 数学 2019-12-17 Xin Zhang , Bei Niu , Jiguo Yu

The reconfiguration graph $R_k(G)$ for the $k$-colorings of a graph $G$ has as vertices all possible $k$-colorings of $G$ and two colorings are adjacent if they differ in the color of exactly one vertex. We use a list coloring technique…

组合数学 · 数学 2020-06-17 Zdeněk Dvořák , Carl Feghali

We develop an algorithmic framework for graph colouring that reduces the problem to verifying a local probabilistic property of the independent sets. With this we give, for any fixed $k\ge 3$ and $\varepsilon>0$, a randomised…

数据结构与算法 · 计算机科学 2020-04-16 Ewan Davies , Ross J. Kang , François Pirot , Jean-Sébastien Sereni