Two results on K-(2,1)-total choosability of planar graphs

Abstract

The [Formula: see text]-total choice number of [Formula: see text], denoted by [Formula: see text], is the minimum [Formula: see text] such that [Formula: see text] is [Formula: see text]-[Formula: see text]-total choosable. It was proved in [Y. Yu, X. Zhang and G. Z. Liu, List (d,1)-total labeling of graphs embedded in surfaces, Oper. Res. Trans. 15(3) (2011) 29–37.] that [Formula: see text] if [Formula: see text] is a graph embedded in surface with Euler characteristic [Formula: see text] and [Formula: see text] big enough. In this paper, we prove that: (i) if [Formula: see text] is a planar graph with [Formula: see text] and [Formula: see text]-cycle is not adjacent to [Formula: see text]-cycle, [Formula: see text], then [Formula: see text]; (ii) if [Formula: see text] is a planar graph with [Formula: see text] and [Formula: see text]-cycle is not adjacent to [Formula: see text]-cycle, where [Formula: see text], then [Formula: see text].