∀ {α : Type u_1} {δ : Type u_4} [inst : TopologicalSpace α] {mα : MeasurableSpace α} [OpensMeasurableSpace α]
  {mδ : MeasurableSpace δ} [inst_2 : LinearOrder α] [SecondCountableTopology α] [OrderClosedTopology α]
  {μ : MeasureTheory.Measure δ} {f g : δ → α},
  AEMeasurable f μ → AEMeasurable g μ → MeasureTheory.NullMeasurableSet {a | f a ≤ g a} μ