English
The closure in the additive world of the multiplicative image corresponds to AddSubgroup closure of the preimage under Multiplicative.ofAdd.
Русский
Замыкание в аддитивной вселенной образа через Multiplicative.ofAdd соответствует AddSubgroup.closure предобразу.
LaTeX
$$$ (\mathrm{closure} S).\mathrm{toAddSubgroup'} = \mathrm{AddSubgroup.closure}(\mathrm{Multiplicative.ofAdd}^{-1} S) $$$
Lean4
theorem _root_.AddSubgroup.toSubgroup_closure {A : Type*} [AddGroup A] (S : Set A) :
(AddSubgroup.closure S).toSubgroup = Subgroup.closure (Multiplicative.toAdd ⁻¹' S) :=
Subgroup.toAddSubgroup.injective (Subgroup.toAddSubgroup_closure _).symm