Probing Graph Proper Total Colorings With Additional Constrained   Conditions
  Graph colorings are becoming an increasingly useful family of mathematical models for a broad range of applications, such as time tabling and scheduling, frequency assignment, register allocation, computer security and so on. Graph proper total colorings with additional constrained conditions have been investigated intensively in the last decade year. In this article some new graph proper total colorings with additional constrained conditions are defined, and approximations to the chromatic numbers of these colorings are researched, as well as some graphs having these colorings have been verified. 
Bing Yao, Ming Yao, Xiang-en Chen
math.CO cs.IT math.IT