不包括4轮
Excluding 4-wheels
摘要：
4轮图是由圈C和不在C中的顶点形成的图，该顶点在C中至少有四个邻居。证明了不含4轮子图的图G是4-可着色的，并描述了这类图的一些结构性质。
英文摘要：
A 4-wheel is a graph formed by a cycle C and a vertex not in C that has at least four neighbors in C. We prove that a graph G that does not contain a 4-wheel as a subgraph is 4-colorable and we describe some structural properties of such a graph.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
