设Hn(n≥5)表示一个图一以1,2,…,n为顶点,两个点i和j是相邻的当且仅当|i-j|≤2,其中加法取模n.这篇文章证明了;Hn的色数等于它的选择数.结果被用于刻画最大度至多2的图的列表全色数.
A graph is chromatic-choosable if its choice number coincides with its chromatic number. Let Hn (n ≥ 5) denote the graph with vertices 1, 2,…, n and two vertices i and j being adjacent if and only if |i-j|≤ 2, where addition is taken modulo n. In this paper we prove that Hn is chromatic-choosable. The result is applied to characterize the list total chromatic number of graphs with maximum degree at most two.