Talk:Permutation graph

This is a very useful article. My thanks to the authors! A small correction though: the easy result "A graph G is a permutation graph if and only if G is a circle graph that admits an equator" is improperly cited. I do not know its origin but it appears as an exercise in Golumbic's book. Lorenzo Traldi (talk) 11:24, 22 March 2015 (UTC)
 * The citation given in the article is not to a research article where this originally appears, but a book surveying graph classes and their properties. The ctation is is not so much intended to give credit to someone for a discovery, as to make it possible for suspicious readers to check whether the claim is attested in the literatur; see WP:V. —David Eppstein (talk) 17:01, 22 March 2015 (UTC)