English
For a set s, the natural-span closure of s equals the span over the natural numbers; i.e., the submodule generated by the closure of s under addition is the same as the ℕ-span of s.
Русский
Для множества s подмодуль, полученный какNat-спан closure(s), равен спану по натуал-коэффициентам множества s.
LaTeX
$$$ (\operatorname{AddSubmonoid.closure} s)^{\mathrm{toNatSubmodule}} = \operatorname{span}_{\mathbb{N}}(s) $$
Lean4
theorem _root_.AddSubmonoid.toNatSubmodule_closure (s : Set M) : (AddSubmonoid.closure s).toNatSubmodule = .span ℕ s :=
(Submodule.span_le.mpr AddSubmonoid.subset_closure).antisymm'
((Submodule.span ℕ s).toAddSubmonoid.closure_le.mpr Submodule.subset_span)