is mentioned by

Thm* For any graph the_obj:GraphObject(the_graph), P,Q:(V). (x:V. P(x) Q(x)) (x:V. P(x) & Q(x)) vertex-count(the_obj;x.P(x)) < vertex-count(the_obj;x.Q(x))	[vertex-count-less]
Thm* For any graph the_obj:GraphObject(the_graph), P,Q:(V). (x:V. P(x) Q(x)) vertex-count(the_obj;x.P(x))vertex-count(the_obj;x.Q(x))	[vertex-count-le]

Try larger context: Graphs