English

A note on adaptable choosability and choosability with separation of planar graphs

Combinatorics 2020-11-02 v1

Abstract

Let FF be a (possibly improper) edge-coloring of a graph GG; a vertex coloring of GG is \emph{adapted to} FF if no color appears at the same time on an edge and on its two endpoints. If for some integer kk, a graph GG is such that given any list assignment LL to the vertices of GG, with L(v)k|L(v)| \ge k for all vv, and any edge-coloring FF of GG, GG admits a coloring cc adapted to FF where c(v)L(v)c(v) \in L(v) for all vv, then GG is said to be \emph{adaptably kk-choosable}. A {\em (k,d)(k,d)-list assignment} for a graph GG is a map that assigns to each vertex vv a list L(v)L(v) of at least kk colors such that L(x)L(y)d|L(x) \cap L(y)| \leq d whenever xx and yy are adjacent. A graph is {\em (k,d)(k,d)-choosable} if for every (k,d)(k,d)-list assignment LL there is an LL-coloring of GG. It has been conjectured that planar graphs are (3,1)(3,1)-choosable. We give some progress on this conjecture by giving sufficient conditions for a planar graph to be adaptably 33-choosable. Since (k,1)(k,1)-choosability is a special case of adaptable kk-choosablity, this implies that a planar graph satisfying these conditions is (3,1)(3,1)-choosable.

Keywords

Cite

@article{arxiv.2010.16190,
  title  = {A note on adaptable choosability and choosability with separation of planar graphs},
  author = {Carl Johan Casselgren and Jonas B. Granholm and André Raspaud},
  journal= {arXiv preprint arXiv:2010.16190},
  year   = {2020}
}

Comments

To appear in JCMCC

R2 v1 2026-06-23T19:46:26.131Z