Some results on total weight choosability

Abstract

A graph $G=(V,E)$ is called $(k,k^{\prime })$-choosable if for any total list assignment $L$ which assigns to each vertex $v$ a set $L(v)$ of $k$ real numbers, and assigns to each edge $e$ a set $L(e)$ of $k^{\prime }$ real numbers, there is a mapping $f:V\cup E\to \mathbb{R}$ such that $f(y)\in L(y)$ for any $y\in V\cup E$ and for any two adjacent vertices $v,v^{\prime }$, ${\sum }_{e\in E(v)}f(e)+f(v)\ne {\sum }_{e\in E(v^{\prime })}f(e)+f(v^{\prime })$, where $E(x)$ denotes the set of incident edges of a vertex $x\in V(G)$. In this paper, we characterize a sufficient condition on $(1,2)$-choosable of graphs. We show that every connected $(n,m)$-graph is both $(2,2)$-choosable and $(1,3)$-choosable if $m=n$ or $n+1$, where $(n,m)$-graph denotes the graph with $n$ vertices and $m$ edges. Furthermore, we prove that some graphs obtained by some graph operations are $(2,2)$-choosable.