(* Basic constructions ******************************************************)
lemma list_append_empty_sn (A):
- â\88\80l2. l2 = â\92º ⨁{A} l2.
+ â\88\80l2. l2 = â\93\94 ⨁{A} l2.
// qed.
lemma list_append_lcons_sn (A):
(* Advanced constructions ***************************************************)
lemma list_append_empty_dx (A):
- â\88\80l1. l1 = l1 â¨\81{A} â\92º.
+ â\88\80l1. l1 = l1 â¨\81{A} â\93\94.
#A #l1 elim l1 -l1
[ <list_append_empty_sn //
| #hd #tl #IH <list_append_lcons_sn <IH //