(* Constructions with tr_compose and tr_tls *********************************)
+lemma tr_tls_compose_uni_sn (f) (n) (p:pnat):
+ ā*[p]f ā ā*[p](š®āØnā©āf).
+#f #n #p elim p -p //
+#p #IH /2 width=1 by stream_tl_eq_repl/
+qed.
+
lemma tr_tl_compose_uni_dx (f) (n):
ā*[ān]f ā ā(fāš®āØnā©).
// qed.