--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||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/rt_transition/cpg_drops.ma".
+include "basic_2/rt_transition/cpx.ma".
+
+(* UNCOUNTED CONTEXT-SENSITIVE PARALLEL REDUCTION FOR TERMS *****************)
+
+(* Advanced properties ******************************************************)
+
+(* Basic_2A1: was: cpx_delta *)
+lemma cpx_delta_drops: ∀h,I,G,L,K,V,V2,W2,i.
+ ⬇*[i] L ≡ K.ⓑ{I}V → ⦃G, K⦄ ⊢ V ➡[h] V2 →
+ ⬆*[⫯i] V2 ≡ W2 → ⦃G, L⦄ ⊢ #i ➡[h] W2.
+#h * #G #L #K #V #V2 #W2 #i #HLK *
+/3 width=7 by cpg_ell_drops, cpg_delta_drops, ex_intro/
+qed.
+
+(* Advanced inversion lemmas ************************************************)
+
+(* Basic_2A1: was: cpx_inv_atom1 *)
+lemma cpx_inv_atom1_drops: ∀h,I,G,L,T2. ⦃G, L⦄ ⊢ ⓪{I} ➡[h] T2 →
+ ∨∨ T2 = ⓪{I}
+ | ∃∃s. T2 = ⋆(next h s) & I = Sort s
+ | ∃∃J,K,V,V2,i. ⬇*[i] L ≡ K.ⓑ{J}V & ⦃G, K⦄ ⊢ V ➡[h] V2 &
+ ⬆*[⫯i] V2 ≡ T2 & I = LRef i.
+#h #I #G #L #T2 * #c #H elim (cpg_inv_atom1_drops … H) -H *
+/4 width=9 by or3_intro0, or3_intro1, or3_intro2, ex4_5_intro, ex2_intro, ex_intro/
+qed-.
+
+(* Basic_2A1: was: cpx_inv_lref1 *)
+lemma cpx_inv_lref1_drops: ∀h,G,L,T2,i. ⦃G, L⦄ ⊢ #i ➡[h] T2 →
+ T2 = #i ∨
+ ∃∃J,K,V,V2. ⬇*[i] L ≡ K. ⓑ{J}V & ⦃G, K⦄ ⊢ V ➡[h] V2 &
+ ⬆*[⫯i] V2 ≡ T2.
+#h #G #L #T1 #i * #c #H elim (cpg_inv_lref1_drops … H) -H *
+/4 width=7 by ex3_4_intro, ex_intro, or_introl, or_intror/
+qed-.
+
+(* Properties with generic slicing for local environments *******************)
+
+(* Basic_2A1: includes: cpx_lift *)
+lemma cpx_lifts: ∀h,G. d_liftable2 (cpx h G).
+#h #G #K #T1 #T2 * #cT #HT12 #b #f #L #HLK #U1 #HTU1
+elim (cpg_lifts … HT12 … HLK … HTU1) -K -T1
+/3 width=4 by ex2_intro, ex_intro/
+qed-.
+
+(* Inversion lemmas with generic slicing for local environments *************)
+
+(* Basic_2A1: includes: cpx_inv_lift1 *)
+lemma cpx_inv_lift1: ∀h,G. d_deliftable2_sn (cpx h G).
+#h #G #L #U1 #U2 * #cU #HU12 #b #f #K #HLK #T1 #HTU1
+elim (cpg_inv_lifts1 … HU12 … HLK … HTU1) -L -U1
+/3 width=4 by ex2_intro, ex_intro/
+qed-.