(* "BIG TREE" PARALLEL COMPUTATION FOR CLOSURES *****************************)
+(* Main properties **********************************************************)
+
theorem yprs_trans: ∀h,g. tri_transitive … (yprs h g).
/2 width=5/ qed-.
+
+(* Advanced properties ******************************************************)
+
+lemma cpr_lpr_ssta_yprs: ∀h,g,G,L1,L2,T1,T2,U2,l2.
+ ⦃G, L1⦄ ⊢ T1 ➡ T2 → ⦃G, L1⦄ ⊢ ➡ L2 →
+ ⦃G, L2⦄ ⊢ T2 ▪[h, g] l2+1 → ⦃G, L2⦄ ⊢ T2 •[h, g] U2 →
+ ⦃G, L1, T1⦄ ≥[h, g] ⦃G, L2, U2⦄.
+/3 width=5 by yprs_trans, cpr_lpr_yprs, ssta_yprs/ qed.