Is the empty graph cograph
20 views
Skip to first unread message
Jori Mäntysalo
Oct 12, 2017, 11:18:33 AM10/12/17
to sage-...@googlegroups.com
Should the empty graph be defined as cograph?
It can not be made from 1-vertex graphs by disjoint union and
complementation, so it is not. OTOH it has no induced subgraph isomorphic
to 4-vertex path, and it is the comparibility graph of the empty poset, so
it kind of is.
--
Jori Mäntysalo
It can not be made from 1-vertex graphs by disjoint union and
complementation, so it is not. OTOH it has no induced subgraph isomorphic
to 4-vertex path, and it is the comparibility graph of the empty poset, so
it kind of is.
--
Jori Mäntysalo
Reply all
Reply to author
Forward
0 new messages