English
Noncomputable equivalence between PartENat and ℕ∞ exists with toWithTop and its inverse.
Русский
Существует невычислимое эквивалентность между PartENat и ℕ∞ с помощью toWithTop и его обратной функции.
LaTeX
$$$\\\\text{withTopEquiv} : PartENat \\simeq \\mathbb{N}_{\\infty}$$$
Lean4
/-- `Equiv` between `PartENat` and `ℕ∞` (for the order isomorphism see
`withTopOrderIso`). -/
@[simps]
noncomputable def withTopEquiv : PartENat ≃ ℕ∞
where
toFun x := toWithTop x
invFun x := ↑x
left_inv x := by simp
right_inv x := by simp