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

Lemma same_side__plane : forall A B l, same_side A B l -> exists p, IncidP A p /\ IncidP B p /\ IncidLP l p.