平面图的理论与四色问题(Ⅳ)——三着色与四色问题的几何表征

Planar Graph Theory and the Four Color Problem (Ⅳ) -Three Colorings and Geometric theory of the Four Color Problem

中文摘要:

      

英文摘要:

      This is the fourth part of the series of five papers about planar graph theory and the four color problem.It contains the following five sections. §16 Three color problems;§17 The Tait coloring of edges, §18 The four color problem and chain groups; §19 Proje-ctive geometry and the four color problem; §20 On the number of four colorings.