From: Ferruccio Guidi <ferruccio.guidi@unibo.it>
Date: Sat, 26 Oct 2013 17:47:20 +0000 (+0000)
Subject: - bug fix in the connection between global and restricted big-tree
X-Git-Tag: make_still_working~1063
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=b3c3ea1c87cbd7a87c8c29a276fc16f9ebbfb5bd;p=helm.git

- bug fix in the connection between global and restricted big-tree
proper computation
- one file was not committed :(
---

diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/cpxs_lift.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/cpxs_lift.ma
index 8028270d6..0c9cfe1e7 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/cpxs_lift.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/cpxs_lift.ma
@@ -71,31 +71,43 @@ qed-.
 
 (* Properties on supclosure *************************************************)
 
+lemma fqu_cpxs_trans: ∀h,g,G1,G2,L1,L2,T2,U2. ⦃G2, L2⦄ ⊢ T2 ➡*[h, g] U2 →
+                      ∀T1. ⦃G1, L1, T1⦄ ⊃ ⦃G2, L2, T2⦄ →
+                      ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃ ⦃G2, L2, U2⦄.
+#h #g #G1 #G2 #L1 #L2 #T2 #U2 #H @(cpxs_ind_dx … H) -T2 /2 width=3 by ex2_intro/
+#T #T2 #HT2 #_ #IHTU2 #T1 #HT1 elim (fqu_cpx_trans … HT1 … HT2) -T
+#T #HT1 #HT2 elim (IHTU2 … HT2) -T2 /3 width=3 by cpxs_strap2, ex2_intro/
+qed-.
+
 lemma fquq_cpxs_trans: ∀h,g,G1,G2,L1,L2,T2,U2. ⦃G2, L2⦄ ⊢ T2 ➡*[h, g] U2 →
                        ∀T1. ⦃G1, L1, T1⦄ ⊃⸮ ⦃G2, L2, T2⦄ →
-                       ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃* ⦃G2, L2, U2⦄.
-#h #g #G1 #G2 #L1 #L2 #T2 #U2 #H @(cpxs_ind_dx … H) -T2
-[ /3 width=3 by fquq_fqus, ex2_intro/
-| #T #T2 #HT2 #_ #IHTU2 #T1 #HT1
-  elim (fquq_cpx_trans … HT1 … HT2) -T #T #HT1 #HT2
-  elim (IHTU2 … HT2) -T2 /3 width=3 by cpxs_strap2, ex2_intro/
+                       ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃⸮ ⦃G2, L2, U2⦄.
+#h #g #G1 #G2 #L1 #L2 #T2 #U2 #HTU2 #T1 #H elim (fquq_inv_gen … H) -H
+[ #HT12 elim (fqu_cpxs_trans … HTU2 … HT12) /3 width=3 by fqu_fquq, ex2_intro/
+| * #H1 #H2 #H3 destruct /2 width=3 by ex2_intro/
 ]
 qed-.
 
 lemma fquq_lsstas_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃⸮ ⦃G2, L2, T2⦄ →
                          ∀U2,l1. ⦃G2, L2⦄ ⊢ T2 •*[h, g, l1] U2 →
                          ∀l2. ⦃G2, L2⦄ ⊢ T2 ▪ [h, g] l2 → l1 ≤ l2 →
-                         ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃* ⦃G2, L2, U2⦄.
+                         ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃⸮ ⦃G2, L2, U2⦄.
 /3 width=5 by fquq_cpxs_trans, lsstas_cpxs/ qed-.
 
-lemma fqus_cpxs_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃* ⦃G2, L2, T2⦄ →
-                       ∀U2. ⦃G2, L2⦄ ⊢ T2 ➡*[h, g] U2 →
+lemma fqup_cpxs_trans: ∀h,g,G1,G2,L1,L2,T2,U2. ⦃G2, L2⦄ ⊢ T2 ➡*[h, g] U2 →
+                       ∀T1. ⦃G1, L1, T1⦄ ⊃+ ⦃G2, L2, T2⦄ →
+                       ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃+ ⦃G2, L2, U2⦄.
+#h #g #G1 #G2 #L1 #L2 #T2 #U2 #H @(cpxs_ind_dx … H) -T2 /2 width=3 by ex2_intro/
+#T #T2 #HT2 #_ #IHTU2 #T1 #HT1 elim (fqup_cpx_trans … HT1 … HT2) -T
+#U1 #HTU1 #H2 elim (IHTU2 … H2) -T2 /3 width=3 by cpxs_strap2, ex2_intro/
+qed-.
+
+lemma fqus_cpxs_trans: ∀h,g,G1,G2,L1,L2,T2,U2. ⦃G2, L2⦄ ⊢ T2 ➡*[h, g] U2 →
+                       ∀T1. ⦃G1, L1, T1⦄ ⊃* ⦃G2, L2, T2⦄ →
                        ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃* ⦃G2, L2, U2⦄.
-#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H @(fqus_ind … H) -G2 -L2 -T2
-[ /2 width=3 by ex2_intro/
-| #G #G2 #L #L2 #T #T2 #_ #HT2 #IHT1 #U2 #HTU2
-  elim (fquq_cpxs_trans … HTU2 … HT2) -T2 #T2 #HT2 #HTU2
-  elim (IHT1 … HT2) -T /3 width=7 by fqus_trans, ex2_intro/
+#h #g #G1 #G2 #L1 #L2 #T2 #U2 #HTU2 #T1 #H elim (fqus_inv_gen … H) -H
+[ #HT12 elim (fqup_cpxs_trans … HTU2 … HT12) /3 width=3 by fqup_fqus, ex2_intro/
+| * #H1 #H2 #H3 destruct /2 width=3 by ex2_intro/
 ]
 qed-.
 
@@ -104,14 +116,3 @@ lemma fqus_lsstas_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃* ⦃G2,
                          ∀l2. ⦃G2, L2⦄ ⊢ T2 ▪ [h, g] l2 → l1 ≤ l2 →
                          ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] U1 & ⦃G1, L1, U1⦄ ⊃* ⦃G2, L2, U2⦄.
 /3 width=7 by fqus_cpxs_trans, lsstas_cpxs/ qed-.
-
-lemma fqus_cpx_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃* ⦃G2, L2, T2⦄ →
-                      ∀U2. ⦃G2, L2⦄ ⊢ T2 ➡[h, g] U2 →
-                      ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡[h, g] U1 & ⦃G1, L1, U1⦄ ⊃* ⦃G2, L2, U2⦄.
-#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H @(fqus_ind … H) -G2 -L2 -T2
-[ /2 width=3 by ex2_intro/
-| #G #G2 #L #L2 #T #T2 #_ #HT2 #IHT1 #U2 #HTU2
-  elim (fquq_cpx_trans … HT2 … HTU2) -T2 #T2 #HT2 #HTU2
-  elim (IHT1 … HT2) -T /3 width=7 by fqus_strap1, ex2_intro/
-]
-qed-.
diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg.ma
index 29cbd8d5d..faf5dd7d9 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg.ma
@@ -18,6 +18,7 @@ include "basic_2/computation/fpbs.ma".
 
 (* GENEARAL "BIG TREE" PROPER PARALLEL COMPUTATION FOR CLOSURES *************)
 
+(* Note: this is not transitive *)
 inductive fpbg (h) (g) (G1) (L1) (T1): relation3 genv lenv term ≝
 | fpbg_cpxs: ∀L2,T2. ⦃G1, L1⦄ ⊢ T1 ➡*[h, g] T2 → (T1 = T2 → ⊥) → ⦃G1, L1⦄ ⊢ ➡*[h, g] L2 →
              fpbg h g G1 L1 T1 G1 L2 T2
@@ -35,21 +36,3 @@ lemma fpbc_fpbg: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ≻[h, g] ⦃G2, L2,
 #h #g #G1 #G2 #L1 #L2 #T1 #T2 * -G2 -L2 -T2
 /3 width=5 by fpbg_cpxs, fpbg_fqup, fqu_fqup, cpx_cpxs/
 qed.
-
-axiom fpbg_strap1: ∀h,g,G1,G,G2,L1,L,L2,T1,T,T2. ⦃G1, L1, T1⦄ >[h, g] ⦃G, L, T⦄ →
-                   ⦃G, L, T⦄ ≽[h, g] ⦃G2, L2, T2⦄ → ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄.
-
-axiom fpbg_strap2: ∀h,g,G1,G,G2,L1,L,L2,T1,T,T2. ⦃G1, L1, T1⦄ ≽[h, g] ⦃G, L, T⦄ →
-                   ⦃G, L, T⦄ >[h, g] ⦃G2, L2, T2⦄ → ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄.
-
-lemma fpbg_fpbs_trans: ∀h,g,G1,G,G2,L1,L,L2,T1,T,T2. ⦃G1, L1, T1⦄ >[h, g] ⦃G, L, T⦄ →
-                       ⦃G, L, T⦄ ≥[h, g] ⦃G2, L2, T2⦄ → ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄.
-#h #g #G1 #G #G2 #L1 #L #L2 #T1 #T #T2 #H1 #H @(fpbs_ind … H) -G2 -L2 -T2
-/2 width=5 by fpbg_strap1/
-qed-.
-
-lemma fpbs_fpbg_trans: ∀h,g,G1,G,G2,L1,L,L2,T1,T,T2. ⦃G1, L1, T1⦄ ≥[h, g] ⦃G, L, T⦄ →
-                       ⦃G, L, T⦄ >[h, g] ⦃G2, L2, T2⦄ → ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄.
-#h #g #G1 #G #G2 #L1 #L #L2 #T1 #T #T2 #H @(fpbs_ind_dx … H) -G1 -L1 -T1
-/3 width=5 by fpbg_strap2/
-qed-.
diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg_fpbg.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg_fpbg.ma
new file mode 100644
index 000000000..047aee3d4
--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbg_fpbg.ma
@@ -0,0 +1,36 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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/computation/fpbs_alt.ma".
+include "basic_2/computation/fpbs_fpbs.ma".
+include "basic_2/computation/fpbg.ma".
+
+(* GENERAL "BIG TREE" PROPER PARALLEL COMPUTATION FOR CLOSURES **************)
+
+(* Advanced forward lemmas **************************************************)
+
+lemma fpbg_fwd_fpbs: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄ →
+                     ⦃G1, L1, T1⦄ ≥[h, g] ⦃G2, L2, T2⦄.
+#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H elim H -G2 -L2 -T2
+/3 width=5 by cpxs_fqup_fpbs, fpbs_trans, lpxs_fpbs, cpxs_fpbs/
+qed-.
+
+(* Advanced properties ******************************************************)
+
+lemma fqu_fpbs_fpbg: ∀h,g,G1,G,G2,L1,L,L2,T1,T,T2. ⦃G1, L1, T1⦄ ⊃ ⦃G, L, T⦄ →
+                     ⦃G, L, T⦄ ≥[h, g] ⦃G2, L2, T2⦄ → ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄.
+#h #g #G1 #G #G2 #L1 #L #L2 #T1 #T #T2 #H1 #H elim(fpbs_fpbsa … H) -H
+#L0 #T0 #HT0 #HT02 #HL02 elim (fqu_cpxs_trans … HT0 … H1) -T
+/3 width=7 by fpbg_fqup, fqus_strap2_fqu/
+qed.
diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr.ma
index 099567d41..04f0e2309 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr.ma
@@ -13,7 +13,7 @@
 (**************************************************************************)
 
 include "basic_2/notation/relations/btpredstarrestricted_8.ma".
-include "basic_2/computation/fpbg.ma".
+include "basic_2/computation/fpbs.ma".
 
 (* RESTRICTED "BIG TREE" PROPER PARALLEL COMPUTATION FOR CLOSURES ***********)
 
@@ -26,14 +26,16 @@ inductive fpbr (h) (g) (G1) (L1) (T1): relation3 genv lenv term ≝
 interpretation "restricted 'big tree' proper parallel computation (closure)"
    'BTPRedStarRestricted h g G1 L1 T1 G2 L2 T2 = (fpbr h g G1 L1 T1 G2 L2 T2).
 
-(* Basic forward lemmas *****************************************************)
+(* Basic inversion lemmas ***************************************************)
 
-lemma fpbr_fwd_fpbg: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃≥[h, g] ⦃G2, L2, T2⦄ →
-                     ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄.
-#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H elim H -G2 -L2 -T2
-/3 width=5 by fpbg_strap1, fpbc_fpbg, fpbc_fqu/
+lemma fpbr_inv_fqu_fpbs: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃≥[h, g] ⦃G2, L2, T2⦄ →
+                         ∃∃G,L,T. ⦃G1, L1, T1⦄ ⊃ ⦃G, L, T⦄ & ⦃G, L, T⦄ ≥[h, g] ⦃G2, L2, T2⦄.
+#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H elim H -G2 -L2 -T2 [ /2 width=5 by ex2_3_intro/ ] (**) (* auto fails without brackets *)
+#G #G2 #L #L2 #T #T2 #_ #HT2 * /3 width=9 by fpbs_strap1, ex2_3_intro/
 qed-.
 
+(* Basic forward lemmas *****************************************************)
+
 lemma fpbr_fwd_fpbs: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃≥[h, g] ⦃G2, L2, T2⦄ →
                      ⦃G1, L1, T1⦄ ≥[h, g] ⦃G2, L2, T2⦄.
 #h #g #G1 #G2 #L1 #L2 #T1 #T2 #H elim H -G2 -L2 -T2
diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr_fpbr.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr_fpbr.ma
index 786030aff..f0d79dc33 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr_fpbr.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbr_fpbr.ma
@@ -18,6 +18,13 @@ include "basic_2/computation/fpbr.ma".
 (* RESTRICTED "BIG TREE" ORDER FOR CLOSURES *********************************)
 
 (* Advanced forward lemmas **************************************************)
+
+lemma fpbr_fwd_fpbg: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃≥[h, g] ⦃G2, L2, T2⦄ →
+                     ⦃G1, L1, T1⦄ >[h, g] ⦃G2, L2, T2⦄.
+#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H elim (fpbr_inv_fqu_fpbs … H) -H
+/2 width=5 by fqu_fpbs_fpbg/
+qed-.
+
 lemma fpbr_fwd_fpbs: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃≥[h, g] ⦃G2, L2, T2⦄ →
                      ⦃G1, L1, T1⦄ ≥[h, g] ⦃G2, L2, T2⦄.
 /3 width=5 by fpbr_fwd_fpbg, fpbg_fwd_fpbs/
diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbs_alt.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbs_alt.ma
index 9e5336c04..36fc55264 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/fpbs_alt.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/fpbs_alt.ma
@@ -32,10 +32,10 @@ interpretation "'big tree' parallel computation (closure) alternative"
 
 lemma fpb_fpbsa_trans: ∀h,g,G1,G,L1,L,T1,T. ⦃G1, L1, T1⦄ ≽[h, g] ⦃G, L, T⦄ →
                        ∀G2,L2,T2. ⦃G, L, T⦄ ≥≥[h, g] ⦃G2, L2, T2⦄ → ⦃G1, L1, T1⦄ ≥≥[h, g] ⦃G2, L2, T2⦄.
-#h #g #G1 #G #L1 #L #T1 #T * -G -L -T [ #G #L #T #HG1 | #T #HT1 | #L #HL1 ]   
+#h #g #G1 #G #L1 #L #T1 #T * -G -L -T [ #G #L #T #HG1 | #T #HT1 | #L #HL1 ]
 #G2 #L2 #T2 * #L0 #T0 #HT0 #HG2 #HL02
 [ elim (fquq_cpxs_trans … HT0 … HG1) -T
-  /3 width=7 by fqus_trans, ex3_2_intro/
+  /3 width=7 by fqus_strap2, ex3_2_intro/
 | /3 width=5 by cpxs_strap2, ex3_2_intro/
 | lapply (lpx_cpxs_trans … HT0 … HL1) -HT0
   elim (lpx_fqus_trans … HG2 … HL1) -L
diff --git a/matita/matita/contribs/lambdadelta/basic_2/computation/lpxs_cpxs.ma b/matita/matita/contribs/lambdadelta/basic_2/computation/lpxs_cpxs.ma
index 2d197c95b..10600383a 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/computation/lpxs_cpxs.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/computation/lpxs_cpxs.ma
@@ -107,7 +107,7 @@ lemma lpxs_fqus_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃* ⦃G2, L2
 #h #g #G1 #G2 #L1 #L2 #T1 #T2 #H @(fqus_ind … H) -G2 -L2 -T2 /2 width=5 by ex3_2_intro/
 #G #G2 #L #L2 #T #T2 #_ #H2 #IH1 #K1 #HLK1 elim (IH1 … HLK1) -L1
 #L0 #T0 #HT10 #HT0 #HL0 elim (lpxs_fquq_trans … H2 … HL0) -L
-#L #T3 #HT3 #HT32 #HL2 elim (fqus_cpxs_trans … HT0 … HT3) -T
+#L #T3 #HT3 #HT32 #HL2 elim (fqus_cpxs_trans … HT3 … HT0) -T
 /3 width=7 by cpxs_trans, fqus_strap1, ex3_2_intro/
 qed-.
 
diff --git a/matita/matita/contribs/lambdadelta/basic_2/reduction/cpx_lift.ma b/matita/matita/contribs/lambdadelta/basic_2/reduction/cpx_lift.ma
index eeb23f7b5..505eabf1a 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/reduction/cpx_lift.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/reduction/cpx_lift.ma
@@ -173,6 +173,27 @@ lemma fquq_ssta_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃⸮ ⦃G2,
                        ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡[h, g] U1 & ⦃G1, L1, U1⦄ ⊃⸮ ⦃G2, L2, U2⦄.
 /3 width=5 by fquq_cpx_trans, ssta_cpx/ qed-.
 
+lemma fqup_cpx_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃+ ⦃G2, L2, T2⦄ →
+                      ∀U2. ⦃G2, L2⦄ ⊢ T2 ➡[h, g] U2 →
+                      ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡[h, g] U1 & ⦃G1, L1, U1⦄ ⊃+ ⦃G2, L2, U2⦄.
+#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H @(fqup_ind … H) -G2 -L2 -T2
+[ #G2 #L2 #T2 #H12 #U2 #HTU2 elim (fqu_cpx_trans … H12 … HTU2) -T2
+  /3 width=3 by fqu_fqup, ex2_intro/
+| #G #G2 #L #L2 #T #T2 #_ #HT2 #IHT1 #U2 #HTU2
+  elim (fqu_cpx_trans … HT2 … HTU2) -T2 #T2 #HT2 #HTU2
+  elim (IHT1 … HT2) -T /3 width=7 by fqup_strap1, ex2_intro/
+]
+qed-.
+
+lemma fqus_cpx_trans: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃* ⦃G2, L2, T2⦄ →
+                      ∀U2. ⦃G2, L2⦄ ⊢ T2 ➡[h, g] U2 →
+                      ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡[h, g] U1 & ⦃G1, L1, U1⦄ ⊃* ⦃G2, L2, U2⦄.
+#h #g #G1 #G2 #L1 #L2 #T1 #T2 #H #U2 #HTU2 elim (fqus_inv_gen … H) -H
+[ #HT12 elim (fqup_cpx_trans … HT12 … HTU2) /3 width=3 by fqup_fqus, ex2_intro/
+| * #H1 #H2 #H3 destruct /2 width=3 by ex2_intro/
+]
+qed-.
+
 lemma fqu_cpx_trans_neq: ∀h,g,G1,G2,L1,L2,T1,T2. ⦃G1, L1, T1⦄ ⊃ ⦃G2, L2, T2⦄ →
                          ∀U2. ⦃G2, L2⦄ ⊢ T2 ➡[h, g] U2 → (T2 = U2 → ⊥) →
                          ∃∃U1. ⦃G1, L1⦄ ⊢ T1 ➡[h, g] U1 & T1 = U1 → ⊥ & ⦃G1, L1, U1⦄ ⊃ ⦃G2, L2, U2⦄.