(* Basic_2A1: uses: lleq_lpxs_trans *)
lemma rdeq_lpxs_trans (h) (G) (T:term):
- ∀L2,K2. ⦃G, L2⦄ ⊢ ⬈*[h] K2 →
+ ∀L2,K2. ⦃G,L2⦄ ⊢ ⬈*[h] K2 →
∀L1. L1 ≛[T] L2 →
- ∃∃K1. ⦃G, L1⦄ ⊢ ⬈*[h] K1 & K1 ≛[T] K2.
+ ∃∃K1. ⦃G,L1⦄ ⊢ ⬈*[h] K1 & K1 ≛[T] K2.
#h #G #T #L2 #K2 #H @(lpxs_ind_sn … H) -L2 /2 width=3 by ex2_intro/
#L #L2 #HL2 #_ #IH #L1 #HT
elim (rdeq_lpx_trans … HL2 … HT) -L #L #HL1 #HT
(* Basic_2A1: uses: lpxs_nlleq_inv_step_sn *)
lemma lpxs_rdneq_inv_step_sn (h) (G) (T:term):
- ∀L1,L2. ⦃G, L1⦄ ⊢ ⬈*[h] L2 → (L1 ≛[T] L2 → ⊥) →
- ∃∃L,L0. ⦃G, L1⦄ ⊢ ⬈[h] L & L1 ≛[T] L → ⊥ &
- ⦃G, L⦄ ⊢ ⬈*[h] L0 & L0 ≛[T] L2.
+ ∀L1,L2. ⦃G,L1⦄ ⊢ ⬈*[h] L2 → (L1 ≛[T] L2 → ⊥) →
+ ∃∃L,L0. ⦃G,L1⦄ ⊢ ⬈[h] L & L1 ≛[T] L → ⊥ &
+ ⦃G,L⦄ ⊢ ⬈*[h] L0 & L0 ≛[T] L2.
#h #G #T #L1 #L2 #H @(lpxs_ind_sn … H) -L1
[ #H elim H -H //
| #L1 #L #H1 #H2 #IH2 #H12 elim (rdeq_dec L1 L T) #H