一个地图的每条边,若在同一面的边界上,则称它为奇异地图.由于含环的地图是不可着色的,本文所有地图均不含环.本文研究射影平面和环面上带根奇异地图的色和.
A map is singular if each edge is on the same face on a surface(i.e., those have only one face on a surface). Because any map with loop is not colorable, all maps here are assumed to be loopless. In this paper we present the chromatic enumeration for rooted singular maps on the projective plane and the torus.