Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[Merged by Bors] - chore(FinEnum): List.nthLe -> List.get #12220

Closed
wants to merge 1 commit into from
Closed

[Merged by Bors] - chore(FinEnum): List.nthLe -> List.get #12220

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 4 additions & 5 deletions Mathlib/Data/FinEnum.lean
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -48,13 +48,12 @@ def ofEquiv (α) {β} [FinEnum α] (h : β ≃ α) : FinEnum β
#align fin_enum.of_equiv FinEnum.ofEquiv

/-- create a `FinEnum` instance from an exhaustive list without duplicates -/
def ofNodupList [DecidableEq α] (xs : List α) (h : ∀ x : α, x ∈ xs) (h' : List.Nodup xs) : FinEnum α
where
def ofNodupList [DecidableEq α] (xs : List α) (h : ∀ x : α, x ∈ xs) (h' : List.Nodup xs) :
FinEnum α where
card := xs.length
equiv :=
⟨fun x => ⟨xs.indexOf x, by rw [List.indexOf_lt_length]; apply h⟩, fun ⟨i, h⟩ =>
xs.nthLe _ h, fun x => by simp, fun ⟨i, h⟩ => by
simp [*]⟩
⟨fun x => ⟨xs.indexOf x, by rw [List.indexOf_lt_length]; apply h⟩, xs.get, fun x => by simp,
fun i => by ext; simp [List.get_indexOf h']⟩
#align fin_enum.of_nodup_list FinEnum.ofNodupList

/-- create a `FinEnum` instance from an exhaustive list; duplicates are removed -/
Expand Down
Loading