lean4-htt/tests/lean/run/eq16.lean
2016-09-20 08:32:37 -07:00

17 lines
388 B
Text

open list
variable {A : Type}
set_option pp.implicit true
definition app : list A → list A → list A
| nil l := l
| (h :: t) l := h :: (app t l)
theorem app_nil (l : list A) : app nil l = l :=
rfl
theorem app_cons (h : A) (t l : list A) : app (h :: t) l = h :: (app t l) :=
rfl
example : app ((1:num) :: 2 :: nil) (3 :: 4 :: 5 :: nil) = (1 :: 2 :: 3 :: 4 :: 5 :: nil) :=
rfl