Global Instance IncidLP_morphisml : Proper(EqL ==> eq ==> iff) IncidLP.Global Instance IncidLP_morphismr : Proper(eq ==> EqP ==> iff) IncidLP.

Lemma ncolH_expand : forall A B C, ~ ColH A B C -> ~ ColH A B C /\ A <> B /\ B <> C /\ A <> C.