摘要
We prove a decomposition theorem for graphs that do not contain a subdivision of as an induced subgraph where is the complete graph on four vertices. We obtain also a structure theorem for the class of graphs that contain neither a subdivision of nor a wheel as an induced subgraph, where a wheel is a cycle on at least four vertices together with a vertex that has at least three neighbors on the cycle. Our structure theorem is used to prove that every graph in is 3-colorable and entails a polynomial-time recognition algorithm for membership in . As an intermediate result, we prove a structure theorem for the graphs whose cycles are all chordless.