+qed.
+
+lemma incl_append_l : ∀T,A,B.incl T A (A @ B).
+unfold incl; intros;autobatch.
+qed.
+
+lemma incl_append_r : ∀T,A,B.incl T B (A @ B).
+unfold incl; intros;autobatch.
+qed.
+
+lemma incl_cons : ∀T,A,B,x.incl T A B → incl T (x::A) (x::B).
+unfold incl; intros;elim (in_list_cons_case ? ? ? ? H1);autobatch.
+qed.
+