English
The additive submonoid generated by all square integers equals the nonnegative integers: AddSubmonoid.closure(Set.range(x ↦ x^2)) = AddSubmonoid.nonneg ℤ.
Русский
Аддитивное подмножество, порожденное всеми квадратами целых чисел, равно неотрицательным целым: AddSubmonoid.closure(Set.range(x ↦ x^2)) = AddSubmonoid.nonneg ℤ.
LaTeX
$$$\operatorname{AddSubmonoid.closure}(\operatorname{Set.range}(x \mapsto x^2)) = \operatorname{AddSubmonoid.nonneg}(\mathbb{Z})$$$
Lean4
@[simp]
theorem addSubmonoid_closure_range_mul_self : closure (range fun x : ℤ ↦ x * x) = nonneg _ := by
simpa only [sq] using addSubmonoid_closure_range_pow even_two