“另一个25阶最大平面图”G′_(M25)的四色着色

利用最大平面图着色的"简化降阶法",对一定拓扑结构的"另一个25阶最大平面图"G′_(M25)进行了着色运作.先逐点"降阶",再逐点"着色、升阶、着色",直至获得G′_(M25)的四色着色方案.由于着色过程中,有些点的着色是可以选择的,在这些点作任意选色后,只是找出其中的二个G′_(M25)的四色着色方案,即"四色着色方案壹"和"四色着色方案贰"(其他的四色着色方案未作求解).然后,在"四色着色方案壹"和"四色着色方案贰"的基础上,利用多层次的"二色交换法",相应地分别求出了G′_(M25)的二个相近四色着色方案集,即"相近四色着色方案集壹"和"相近四色着色方案集贰".在"相近四色着色方案集壹"中,含有72个不同的四色着色方案;在"相近四色着色方案集贰"中,含有156个不同的四色着色方案.文中对这二个相近四色着色方案集进行了分析,得到了有意义的结果.

On Four-colorings in"Another Maximal Planar Graph of 25 Order"G'M25

In this paper,two Four-colorings("Four-coloring YI"and"Four-coloring ER")of"another maximal planar graph of 25 order"G′_(m25) are obtained with the"simplified method of reduction of order";and two Near Four-coloring Sets("Near Four-coloring Set YI"and"Near Four-coloring Set ER")of G′_(m25) are obtained with the"method of two-color interchange"too.There are 72 Four-colorings in the"Near Four-coloring Set YI";and there are 156 Four-colorings in the"Near Four-coloring Set ER".The two Near Four-coloring Sets are studied.