English
In general, for a AddSubmonoid s of M, span Nat of its underlying set equals the AddSubmonoid closure of s.
Русский
Для произвольного AddSubmonoid s в M Span Nat от множества s равно замыканию AddSubmonoid от s.
LaTeX
$$$$ (\operatorname{span} \mathbb{N} (s : Set M)).\text{toAddSubmonoid} = \operatorname{AddSubmonoid}.closure s $$$$
Lean4
@[simp]
theorem span_nat_eq (s : AddSubmonoid M) : (span ℕ (s : Set M)).toAddSubmonoid = s := by
rw [span_nat_eq_addSubmonoidClosure, s.closure_eq]