∀l1. l2 ≤ l1 → ⦃G, L⦄ ⊢ T1 ▪[h, g] l1 → ⦃G, L, T1⦄ ≥[h, g] ⦃G, L, T2⦄.
/3 width=5 by cpxs_fpbs, lsstas_cpxs/ qed.
+(* Note: this should be moved *)
lemma ssta_fpbs: ∀h,g,G,L,T,U,l.
⦃G, L⦄ ⊢ T ▪[h, g] l+1 → ⦃G, L⦄ ⊢ T •[h, g] U →
⦃G, L, T⦄ ≥[h, g] ⦃G, L, U⦄.