English
For any measurable set s in G, s * closure{1} = s.
Русский
Для любого измеримого множества s в G выполняется s ⋅ closure{1} = s.
LaTeX
$$$\text{MeasurableSet}(s) \Rightarrow s \cdot \overline{\{1\}} = s$$$
Lean4
@[to_additive]
theorem _root_.MeasurableSet.mul_closure_one_eq {s : Set G} (hs : MeasurableSet s) : s * (closure { 1 } : Set G) = s :=
by
induction s, hs using MeasurableSet.induction_on_open with
| isOpen U hU => exact hU.mul_closure_one_eq
| compl t _ iht => exact compl_mul_closure_one_eq_iff.2 iht
| iUnion f _ _ ihf => simp_rw [iUnion_mul f, ihf]