English
For any subset k of G, the closure of the preimage of k under the inclusion map from closure(k) to G is the whole group, i.e., closure(((↑) : closure(k) → G)^{-1} k) = ⊤.
Русский
Для любого подмножества k группы G замыкание предобраза k по включению из closure(k) в G равно всей группе: closure((↑)^{-1}(k)) = ⊤.
LaTeX
$$$ \operatorname{closure}\big( (\iota: \mathrm{closure}(k) \to G)^{-1}(k) \big) = \top $$$
Lean4
@[to_additive (attr := simp)]
theorem closure_closure_coe_preimage {k : Set G} : closure (((↑) : closure k → G) ⁻¹' k) = ⊤ :=
eq_top_iff.2 fun x _ ↦
Subtype.recOn x fun _ hx' ↦
closure_induction (fun _ h ↦ subset_closure h) (one_mem _) (fun _ _ _ _ ↦ mul_mem) (fun _ _ ↦ inv_mem) hx'