diff --git a/Mathlib/MeasureTheory/MeasurableSpace/Constructions.lean b/Mathlib/MeasureTheory/MeasurableSpace/Constructions.lean index 99dceda0cffb8e..af653b39b48858 100644 --- a/Mathlib/MeasureTheory/MeasurableSpace/Constructions.lean +++ b/Mathlib/MeasureTheory/MeasurableSpace/Constructions.lean @@ -586,6 +586,12 @@ theorem measurable_pi_lambda (f : α → ∀ a, X a) (hf : ∀ a, Measurable fun Measurable f := measurable_pi_iff.mpr hf +lemma MeasurableSpace.comap_process_pi (X : (a : δ) → β → X a) : + MeasurableSpace.comap (fun b a ↦ X a b) inferInstance = + ⨆ a, MeasurableSpace.comap (X a) inferInstance := by + simp_rw [MeasurableSpace.pi, MeasurableSpace.comap_iSup, MeasurableSpace.comap_comp] + rfl + /-- The function `(f, x) ↦ update f a x : (Π a, X a) × X a → Π a, X a` is measurable. -/ @[fun_prop] theorem measurable_update' {a : δ} [DecidableEq δ] :