(* Axiomes simulant les definitions *)

Axiom Rstar':A->A->Prop.
Axiom unfold_Rstar': (P:(A->A->Prop)->Prop)
(P [x,y:A](P:A->A->Prop)
(P x x)->((u:A)(R x u)->(Rstar u y)->(P x y))->(P x y))
->(P Rstar').