On L(2, 1)-Labelings of Oriented Graphs

Abstract

We extend a result of Griggs and Yeh about the maximum possible value of the L(2, 1)-labeling number of a graph in terms of its maximum degree to oriented graphs. We consider the problem both in the usual definition of the oriented L(2, 1)-labeling number and in some variants we introduce.

Keywords

• l(2,1)-labeling
• directed graphs
• 05c78
• 05c20