-lemma teqx_fpbs_trans:
- ∀T1,T. T1 ≅ T →
- ∀G1,G2,L1,L2,T2. ❪G1,L1,T❫ ≥ ❪G2,L2,T2❫ → ❪G1,L1,T1❫ ≥ ❪G2,L2,T2❫.
-/3 width=5 by feqx_fpbs_trans, teqg_feqg/ qed-.
+lemma fpbs_ind_dx:
+ ∀G2,L2,T2. ∀Q:relation3 genv lenv term. Q G2 L2 T2 →
+ (∀G1,G,L1,L,T1,T. ❪G1,L1,T1❫ ≽ ❪G,L,T❫ → ❪G,L,T❫ ≥ ❪G2,L2,T2❫ → Q G L T → Q G1 L1 T1) →
+ ∀G1,L1,T1. ❪G1,L1,T1❫ ≥ ❪G2,L2,T2❫ → Q G1 L1 T1.
+/3 width=8 by tri_TC_star_ind_dx/ qed-.
+
+(* Advanced properties ******************************************************)