+#R #L1 #T1 #T2 * #x #n #f1 #f2 #Hf1 #Hf2 #Hn #Hf #L2 #HL12
+lapply (lveq_inj_length … Hn ?) // #H destruct
+
+
+ Hn : (L1≋ⓧ*[n,n]L1) (L1⊢𝐅*⦃T1⦄≡f1) →
+
+lapply (lfxs_inv_frees … HL12 … Hf2) -HL12 -Hf2 #HL12
+@(ex2_intro … Hf1) -Hf1
+@(sle_lexs_trans … HL12) -HL12 //
+