∀ {α : Type u_1} {β : Type u_2} {mα : MeasurableSpace α} {mβ : MeasurableSpace β} {δ : Type u_4}
  {mδ : MeasurableSpace δ} (κ : ProbabilityTheory.Kernel α β) (γ : Type u_5) {mγ : MeasurableSpace γ} (f : β → δ),
  (ProbabilityTheory.Kernel.prodMkRight γ κ).map f = ProbabilityTheory.Kernel.prodMkRight γ (κ.map f)