The competition-common enemy graphs of digraphs satisfying Conditions $C(p)$ and $C'(p)$
Abstract
S. -R. Kim and F. S. Roberts (2002) introduced the following conditions and for digraphs as generalizations of the condition for digraphs to be semiorders. The condition (resp. ) is: For any set of vertices in , there exists such that (resp. ) for all , where (resp. ) is the set of out-neighbors (resp. in-neighbors) of in . The competition graph of a digraph is the (simple undirected) graph which has the same vertex set as and has an edge between two distinct vertices and if . Kim and Roberts characterized the competition graphs of digraphs which satisfy Condition . The competition-common enemy graph of a digraph is the graph which has the same vertex set as and has an edge between two distinct vertices and if it holds that both and . In this note, we characterize the competition-common enemy graphs of digraphs satisfying Conditions and .
Keywords
Cite
@article{arxiv.1006.2631,
title = {The competition-common enemy graphs of digraphs satisfying Conditions $C(p)$ and $C'(p)$},
author = {Yoshio Sano},
journal= {arXiv preprint arXiv:1006.2631},
year = {2011}
}
Comments
8 pages, 2 figures