max/lean4-htt
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 2

chore: reverse direction of List.tail_map (#5275)

Browse source
This commit is contained in:
Kim Morrison 2024-09-06 21:55:50 +10:00 • committed by GitHub
parent 943dec48c4
commit e5eea67020
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 4 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
src/Init/Data/List/Lemmas.lean
View file

@ -1151,18 +1151,18 @@ theorem map_eq_foldr (f : α → β) (l : List α) : map f l = foldr (fun a bs =
@[simp] theorem head?_map (f : α → β) (l : List α) : head? (map f l) = (head? l).map f := by
cases l <;> rfl
@[simp] theorem tail?_map (f : α → β) (l : List α) : tail? (map f l) = (tail? l).map (map f) := by
@[simp] theorem map_tail? (f : α → β) (l : List α) : (tail? l).map (map f) = tail? (map f l) := by
cases l <;> rfl
@[simp] theorem tail_map (f : α → β) (l : List α) :
(map f l).tail = map f l.tail := by
@[simp] theorem map_tail (f : α → β) (l : List α) :
map f l.tail = (map f l).tail := by
cases l <;> simp_all
theorem headD_map (f : α → β) (l : List α) (a : α) : headD (map f l) (f a) = f (headD l a) := by
cases l <;> rfl
theorem tailD_map (f : α → β) (l : List α) (l' : List α) :
tailD (map f l) (map f l') = map f (tailD l l') := by simp
tailD (map f l) (map f l') = map f (tailD l l') := by simp [← map_tail?]
@[simp] theorem getLast_map (f : α → β) (l : List α) (h) :
getLast (map f l) h = f (getLast l (by simpa using h)) := by