English
There is a canonical way to make multiplication measurable on M by defining left and right translations as measurable maps.
Русский
Существует канонический способ придать измеримость умножению на M через левое и правое перенесение как измеримые отображения.
LaTeX
$$$\\text{MeasurableMul}(M)\\; \\text{exists with left and right translations measurable, i.e. } x \\mapsto a \\cdot x \\text{ and } x \\mapsto x \\cdot a \\text{ are measurable for all } a \\in M.$$$
Lean4
@[to_additive]
instance (priority := 100) toMeasurableMul [MeasurableMul₂ M] : MeasurableMul M :=
⟨fun _ => measurable_const.mul measurable_id, fun _ => measurable_id.mul measurable_const⟩