matita/matita/contribs/lambdadelta/basic_2/rt_transition/fpb_fdeq.ma

   1 (**************************************************************************)
   2 (*       ___                                                              *)
   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
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  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
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  14
  15 include "static_2/s_transition/fqu_tdeq.ma".
  16 include "static_2/static/fdeq.ma".
  17 include "basic_2/rt_transition/fpb_rdeq.ma".
  18
  19 (* PROPER PARALLEL RST-TRANSITION FOR CLOSURES ******************************)
  20
  21 (* Properties with degree-based equivalence for closures ********************)
  22
  23 (* Basic_2A1: uses: fleq_fpb_trans *)
  24 lemma fdeq_fpb_trans: ∀h,F1,F2,K1,K2,T1,T2. ⦃F1, K1, T1⦄ ≛ ⦃F2, K2, T2⦄ →
  25                       ∀G2,L2,U2. ⦃F2, K2, T2⦄ ≻[h] ⦃G2, L2, U2⦄ →
  26                       ∃∃G1,L1,U1. ⦃F1, K1, T1⦄ ≻[h] ⦃G1, L1, U1⦄ & ⦃G1, L1, U1⦄ ≛ ⦃G2, L2, U2⦄.
  27 #h #F1 #F2 #K1 #K2 #T1 #T2 * -F2 -K2 -T2
  28 #K2 #T2 #HK12 #HT12 #G2 #L2 #U2 #H12
  29 elim (tdeq_fpb_trans … HT12 … H12) -T2 #K0 #T0 #H #HT0 #HK0
  30 elim (rdeq_fpb_trans … HK12 … H) -K2 #L0 #U0 #H #HUT0 #HLK0
  31 @(ex2_3_intro … H) -H (**) (* full auto too slow *)
  32 /4 width=3 by fdeq_intro_dx, rdeq_trans, tdeq_rdeq_conf, tdeq_trans/
  33 qed-.
  34
  35 (* Inversion lemmas with degree-based equivalence for closures **************)
  36
  37 (* Basic_2A1: uses: fpb_inv_fleq *)
  38 lemma fpb_inv_fdeq: ∀h,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ≻[h] ⦃G2, L2, T2⦄ →
  39                     ⦃G1, L1, T1⦄ ≛ ⦃G2, L2, T2⦄ → ⊥.
  40 #h #G1 #G2 #L1 #L2 #T1 #T2 * -G2 -L2 -T2
  41 [ #G2 #L2 #T2 #H12 #H elim (fdeq_inv_gen_sn … H) -H
  42   /3 width=11 by rdeq_fwd_length, fqu_inv_tdeq/
  43 | #T2 #_ #HnT #H elim (fdeq_inv_gen_sn … H) -H /2 width=1 by/
  44 | #L2 #_ #HnL #H elim (fdeq_inv_gen_sn … H) -H /2 width=1 by/
  45 ]
  46 qed-.