English
If all α i carry a measurable space structure, then the cylinder of a measurable base is measurable.
Русский
Если у всех α i задана сигма-алгебра измеримости, цилиндр над измеримым основанием измерим.
LaTeX
$$$ \\mathrm{MeasurableSet}(S) \\Rightarrow \\mathrm{MeasurableSet}(\\mathrm{cylinder}(s,S)) $$$
Lean4
theorem _root_.MeasurableSet.cylinder [∀ i, MeasurableSpace (α i)] (s : Finset ι) {S : Set (∀ i : s, α i)}
(hS : MeasurableSet S) : MeasurableSet (cylinder s S) :=
measurable_pi_lambda _ (fun _ ↦ measurable_pi_apply _) hS