The $L(2,1)$-choosability of cycle
نویسندگان
1 Hong Kong Baptist University
2 Hong Kong Baptist University
3 United International College
doi
10.22108/toc.2012.1895چکیده
For a given graph $G=(V,E)$, let $\mathscr L(G)=\{L(v) : v\in V\}$ be a prescribed list assignment. $G$ is $\mathscr L$-$L(2,1)$-colorable if there exists a vertex labeling $f$ of $G$ such that $f(v)\in L(v)$ for all $v \in V$; $|f(u)-f(v)|\geq 2$ if $d_G(u,v) = 1$; and $|f(u)-f(v)| \geq 1$ if $d_G(u,v)=2$. If $G$ is $\mathscr L$-$L(2,1)$-colorable for every list assignment $\mathscr L$ with $|L(v)|\geq k$ for all $v\in V$, then $G$ is said to be $k$-$L(2,1)$-choosable. In this paper, we prove all cycles are $5$-$L(2,1)$-choosable.