Variable p : Cone_law.
Canonical Structure Build_Cone : Cone := Build_NT (Prf_Cone_nt_law p).
End cone_nt.
Coercion Build_Cone : Cone_law >-> Cone.

(*** rewrite rules ***)
Lemma EqC :
forall (tau : Cone) (i j : J) (g : i --> j), tau j =_S tau i o FMor F g.