-(**************************************************************************)
-(* ___ *)
-(* ||M|| *)
-(* ||A|| A project by Andrea Asperti *)
-(* ||T|| *)
-(* ||I|| Developers: *)
-(* ||T|| The HELM team. *)
-(* ||A|| http://helm.cs.unibo.it *)
-(* \ / *)
-(* \ / This file is distributed under the terms of the *)
-(* v GNU General Public License Version 2 *)
-(* *)
-(**************************************************************************)
-
-include "basic_2/substitution/gdrop.ma".
-
-(* GLOBAL ENVIRONMENT SLICING ***********************************************)
-
-(* Main properties **********************************************************)
-
-theorem gdrop_mono: ∀G,G1,e. ⇩[e] G ≡ G1 → ∀G2. ⇩[e] G ≡ G2 → G1 = G2.
-#G #G1 #e #H elim H -G -G1
-[ #G #He #G2 #H
- >(gdrop_inv_gt … H He) -H -He //
-| #G #He #G2 #H
- >(gdrop_inv_eq … H He) -H -He //
-| #I #G #G1 #V #He #_ #IHG1 #G2 #H
- lapply (gdrop_inv_lt … H He) -H -He /2 width=1/
-]
-qed-.
-
-lemma gdrop_dec: ∀G1,G2,e. Decidable (⇩[e] G1 ≡ G2).
-#G1 #G2 #e
-elim (gdrop_total e G1) #G #HG1
-elim (genv_eq_dec G G2) #HG2
-[ destruct /2 width=1/
-| @or_intror #HG12
- lapply (gdrop_mono … HG1 … HG12) -HG1 -HG12 /2 width=1/
-]
-qed-.