e4f2de0a53
This should be tested against Mathlib, but there are conflicts with the `nightly-with-mathlib` branch right now, so I'll wait until tomorrow.
18 lines
565 B
Text
18 lines
565 B
Text
/-
|
||
Copyright (c) 2024 Lean FRO, LLC. All rights reserved.
|
||
Released under Apache 2.0 license as described in the file LICENSE.
|
||
Authors: Markus Himmel
|
||
-/
|
||
prelude
|
||
import Init.Data.Array.Lemmas
|
||
import Init.Data.List.Nat.TakeDrop
|
||
|
||
namespace Array
|
||
|
||
theorem exists_of_uset (self : Array α) (i d h) :
|
||
∃ l₁ l₂, self.toList = l₁ ++ self[i] :: l₂ ∧ List.length l₁ = i.toNat ∧
|
||
(self.uset i d h).toList = l₁ ++ d :: l₂ := by
|
||
simpa only [ugetElem_eq_getElem, getElem_eq_getElem_toList, uset, toList_set] using
|
||
List.exists_of_set _
|
||
|
||
end Array
|