Every toroidal graph without triangles adjacent to $5$-cycles is DP-$4$-colorable
Abstract
DP-coloring, also known as correspondence coloring, is introduced by Dvo{\v{r}}{\'{a}}k and Postle. It is a generalization of list coloring. In this paper, we show that every connected toroidal graph without triangles adjacent to -cycles has minimum degree at most three unless it is a 2-connected -regular graph with Euler characteristic . Consequently, every toroidal graph without triangles adjacent to -cycles is DP--colorable. In the final, we show that every planar graph without two certain subgraphs is DP--colorable. As immediate consequences, (i) every planar graph without -cycles adjacent to -cycles is DP--colorable; (ii) every planar graph without -cycles adjacent to -cycles is DP--colorable; (iii) every planar graph without -cycles adjacent to -cycles is DP--colorable.
Keywords
Cite
@article{arxiv.1803.01197,
title = {Every toroidal graph without triangles adjacent to $5$-cycles is DP-$4$-colorable},
author = {Tao Wang},
journal= {arXiv preprint arXiv:1803.01197},
year = {2019}
}
Comments
All the results are improved and merged into arXiv:1907.07141