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Related papers: $5$-list-coloring toroidal $6$-regular triangulati…

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A Kempe swap in a proper coloring interchanges the colors on some maximal connected 2-colored subgraph. Two $k$-colorings are $k$-equivalent if we can transform one into the other using Kempe swaps. The triangulated toroidal grid,…

Combinatorics · Mathematics 2022-07-07 Daniel W. Cranston , Reem Mahmoud

In 1973, Altshuler characterized the $6$-regular triangulations on the torus to be precisely those that are obtained from a regular triangulation of the $r \times s$ toroidal grid where the vertices in the first and last column are…

Combinatorics · Mathematics 2022-10-11 Brahadeesh Sankarnarayanan

We give an exact characterization of 3-colorability of triangle-free graphs drawn in the torus, in the form of 186 "templates" (graphs with certain faces filled by arbitrary quadrangulations) such that a graph from this class is not…

Combinatorics · Mathematics 2020-09-03 Zdeněk Dvořák , Jakub Pekárek

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…

Combinatorics · Mathematics 2018-03-12 Pongpat Sittitrai , Kittikorn Nakprasit

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…

Combinatorics · Mathematics 2016-12-16 Ilkyoo Choi , Bernard Lidický , Derrick Stolee

An injective coloring of a graph $G$ is an assignment of colors to the vertices of $G$ so that any two vertices with a common neighbor have distinct colors. A graph $G$ is injectively $k$-choosable if for any list assignment $L$, where…

In this work, we introduce DPG-coloring using the concepts of DP-coloring and variable degeneracy to modify the proofs on the following papers: (i) DP-3-coloring of planar graphs without $4$, $9$-cycles and cycles of two lengths from $\{6,…

Combinatorics · Mathematics 2019-08-12 Keaitsuda Maneeruk Nakprasit , Kittikorn Nakprasit

One of Thomassen's classical results is that every planar graph of girth at least $5$ is 3-choosable. One can wonder if for a planar graph $G$ of girth sufficiently large and a $3$-list-assignment $L$, one can do even better. Can one find…

Combinatorics · Mathematics 2023-12-29 Stijn Cambie , Wouter Cames van Batenburg , Xuding Zhu

For positive integers $a$ and $b$, a graph $G$ is $(a:b)$-choosable if, for each assignment of lists of $a$ colors to the vertices of $G,$ each vertex can be colored with a set of $b$ colors from its list so that adjacent vertices are…

Combinatorics · Mathematics 2022-05-23 Glenn G. Chappell

We generalize a framework of list colouring results to correspondence colouring. Correspondence colouring is a generalization of list colouring wherein we localize the meaning of the colours available to each vertex. As pointed out by…

Combinatorics · Mathematics 2023-03-31 Luke Postle , Evelyne Smith-Roberge

In 1994, Thomassen famously proved that every planar graph is 5-choosable, resolving a conjecture initially posed by Vizing and, independently, Erd\H{os}, Rubin, and Taylor in the 1970s. Later, Thomassen proved that every planar graph of…

Combinatorics · Mathematics 2022-12-12 Luke Postle , Evelyne Smith-Roberge

We prove that triangulations with maximum degree at most 5 satisfy the List-Edge-Coloring Conjecture.

Combinatorics · Mathematics 2023-12-15 Joshua Harrelson , Jessica McDonald

Thomassen proved that all planar graphs are $5$-choosable. \v{S}krekovski strengthened the result by showing that all $K_{5}$-minor-free graphs are $5$-choosable. Dvo\v{r}\'{a}k and Postle pointed out that all planar graphs are…

Combinatorics · Mathematics 2022-03-31 Lingxi Li , Tao Wang

This note proves that every graph of Euler genus $\mu$ is $\lceil 2 + \sqrt{3\mu + 3}\,\rceil$--choosable with defect 1 (that is, clustering 2). Thus, allowing defect as small as 1 reduces the choice number of surface embeddable graphs…

Discrete Mathematics · Computer Science 2018-06-19 Vida Dujmović , Djedjiga Outioua

Let $G$ be an $n$-vertex graph and let $L:V(G)\rightarrow P(\{1,2,3\})$ be a list assignment over the vertices of $G$, where each vertex with list of size 3 and of degree at most 5 has at least three neighbors with lists of size 2. We can…

Combinatorics · Mathematics 2021-04-15 Nicholas Crawford , Sogol Jahanbekam

This paper proves the following result: Assume $G$ is a triangle free planar graph, $X$ is an independent set of $G$. If $L$ is a list assignment of $G$ such that $\mid L(v)\mid = 4$ for each vertex $v \in V(G)-X$ and $\mid L(v)\mid = 3$…

Combinatorics · Mathematics 2024-03-05 Jianzhang Hu , Xuding Zhu

For planar graphs, we consider the problems of \emph{list edge coloring} and \emph{list total coloring}. Edge coloring is the problem of coloring the edges while ensuring that two edges that are adjacent receive different colors. Total…

Discrete Mathematics · Computer Science 2014-05-15 Marthe Bonamy , Benjamin Lévêque , Alexandre Pinlou

The concept of DP-coloring of graphs was introduced by Dvo\v{r}\'{a}k and Postle, and was used to prove that planar graphs without cycles of length from $4$ to $8$ are $3$-choosable. In the same paper, they proposed a more natural and…

Combinatorics · Mathematics 2024-12-30 Ligang Jin , Yingli Kang , Xuding Zhu

A graph is (7, 2)-edge-choosable if, for every assignment of lists of size 7 to the edges, it is possible to choose two colors for each edge from its list so that no color is chosen for two incident edges. We show that every…

Combinatorics · Mathematics 2011-10-12 Daniel W. Cranston , Douglas B. West

All planar graphs are 4-colorable and 5-choosable, while some planar graphs are not 4-choosable. Determining which properties guarantee that a planar graph can be colored using lists of size four has received significant attention. In terms…