normalize /2 width=1 by monotonic_le_plus_r/
qed.
+lemma fw_clear: ∀p,I1,I2,G,K,V,T. ♯{G, K.ⓤ{I1}, T} < ♯{G, K, ⓑ{p,I2}V.T}.
+normalize /4 width=1 by monotonic_le_plus_r, le_S_S/
+qed.
+
lemma fw_tpair_sn: ∀I,G,L,V,T. ♯{G, L, V} < ♯{G, L, ②{I}V.T}.
normalize in ⊢ (?→?→?→?→?→?%%); //
qed.