English
There is a scalar action of ℕ on the nonnegative subtype, sending n • ⟨x, hx⟩ to ⟨n • x, nsmul_nonneg hx n⟩.
Русский
Существуют скаляры ℕ, действующие на подпредмет: n • ⟨x, hx⟩ = ⟨n • x, nsmul_nonneg hx n⟩.
LaTeX
$$$nsmul : ℕ \\to SMul ℕ (Subtype (fun x => 0 ≤ x))$ with $nsmul$ preserving nonnegativity$$
Lean4
instance nsmul [AddMonoid α] [Preorder α] [AddLeftMono α] : SMul ℕ { x : α // 0 ≤ x } :=
⟨fun n x => ⟨n • (x : α), nsmul_nonneg x.prop n⟩⟩