+++ /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/syntax/lenv_length.ma".
-include "basic_2/syntax/append.ma".
-
-(* APPEND FOR LOCAL ENVIRONMENTS ********************************************)
-
-(* Properties with length for local environments ****************************)
-
-lemma append_length: ∀L1,L2. |L1 + L2| = |L1| + |L2|.
-#L1 #L2 elim L2 -L2 //
-#L2 #I >append_bind >length_bind >length_bind //
-qed.
-
-lemma ltail_length: ∀I,L. |ⓘ{I}.L| = ↑|L|.
-#I #L >append_length //
-qed.
-
-(* Advanced inversion lemmas on length for local environments ***************)
-
-(* Basic_2A1: was: length_inv_pos_dx_ltail *)
-lemma length_inv_succ_dx_ltail: ∀L,n. |L| = ↑n →
- ∃∃I,K. |K| = n & L = ⓘ{I}.K.
-#Y #n #H elim (length_inv_succ_dx … H) -H #I #L #Hn #HLK destruct
-elim (lenv_case_tail … L) [2: * #K #J ]
-#H destruct /2 width=4 by ex2_2_intro/
-qed-.
-
-(* Basic_2A1: was: length_inv_pos_sn_ltail *)
-lemma length_inv_succ_sn_ltail: ∀L,n. ↑n = |L| →
- ∃∃I,K. n = |K| & L = ⓘ{I}.K.
-#Y #n #H elim (length_inv_succ_sn … H) -H #I #L #Hn #HLK destruct
-elim (lenv_case_tail … L) [2: * #K #J ]
-#H destruct /2 width=4 by ex2_2_intro/
-qed-.
-
-(* Inversion lemmas with length for local environments **********************)
-
-(* Basic_2A1: was: append_inj_sn *)
-lemma append_inj_length_sn: ∀K1,K2,L1,L2. L1 + K1 = L2 + K2 → |K1| = |K2| →
- L1 = L2 ∧ K1 = K2.
-#K1 elim K1 -K1
-[ * /2 width=1 by conj/
- #K2 #I2 #L1 #L2 #_ >length_atom >length_bind
- #H destruct
-| #K1 #I1 #IH *
- [ #L1 #L2 #_ >length_atom >length_bind
- #H destruct
- | #K2 #I2 #L1 #L2 #H1 >length_bind >length_bind #H2
- elim (destruct_lbind_lbind_aux … H1) -H1 #H1 #H3 destruct (**) (* destruct lemma needed *)
- elim (IH … H1) -IH -H1 /3 width=4 by conj/
- ]
-]
-qed-.
-
-(* Note: lemma 750 *)
-(* Basic_2A1: was: append_inj_dx *)
-lemma append_inj_length_dx: ∀K1,K2,L1,L2. L1 + K1 = L2 + K2 → |L1| = |L2| →
- L1 = L2 ∧ K1 = K2.
-#K1 elim K1 -K1
-[ * /2 width=1 by conj/
- #K2 #I2 #L1 #L2 >append_atom >append_bind #H destruct
- >length_bind >append_length >plus_n_Sm
- #H elim (plus_xSy_x_false … H)
-| #K1 #I1 #IH *
- [ #L1 #L2 >append_bind >append_atom #H destruct
- >length_bind >append_length >plus_n_Sm #H
- lapply (discr_plus_x_xy … H) -H #H destruct
- | #K2 #I2 #L1 #L2 >append_bind >append_bind #H1 #H2
- elim (destruct_lbind_lbind_aux … H1) -H1 #H1 #H3 destruct (**) (* destruct lemma needed *)
- elim (IH … H1) -IH -H1 /2 width=1 by conj/
- ]
-]
-qed-.
-
-(* Advanced inversion lemmas ************************************************)
-
-lemma append_inj_dx: ∀L,K1,K2. L+K1 = L+K2 → K1 = K2.
-#L #K1 #K2 #H elim (append_inj_length_dx … H) -H //
-qed-.
-
-lemma append_inv_refl_dx: ∀L,K. L+K = L → K = ⋆.
-#L #K #H elim (append_inj_dx … (⋆) … H) //
-qed-.
-
-lemma append_inv_pair_dx: ∀I,L,K,V. L+K = L.ⓑ{I}V → K = ⋆.ⓑ{I}V.
-#I #L #K #V #H elim (append_inj_dx … (⋆.ⓑ{I}V) … H) //
-qed-.
-
-(* Basic eliminators ********************************************************)
-
-(* Basic_1: was: c_tail_ind *)
-(* Basic_2A1: was: lenv_ind_alt *)
-lemma lenv_ind_tail: ∀Q:predicate lenv.
- Q (⋆) → (∀I,L. Q L → Q (ⓘ{I}.L)) → ∀L. Q L.
-#Q #IH1 #IH2 #L @(f_ind … length … L) -L #x #IHx * //
-#L #I -IH1 #H destruct
-elim (lenv_case_tail … L) [2: * #K #J ]
-#H destruct /3 width=1 by/
-qed-.