Module: Mathlib.Probability.Kernel.RadonNikodym

Goal state before:
pp: α : Type u_1
γ : Type u_2
mα : MeasurableSpace α
mγ : MeasurableSpace γ
κ η : Kernel α γ
hαγ : MeasurableSpace.CountableOrCountablyGenerated α γ
inst✝¹ : IsFiniteKernel κ
inst✝ : IsFiniteKernel η
a : α
s : Set γ
hsm : MeasurableSet s
hs : s ⊆ (κ.mutuallySingularSetSlice η a)ᶜ
this :
  η.withDensity (κ.rnDeriv η) =
    ((κ + η).withDensity fun a x ↦ ↑(1 - κ.rnDerivAux (κ + η) a x).toNNReal).withDensity (κ.rnDeriv η)
hs' : ∀ x ∈ s, κ.rnDerivAux (κ + η) a x < 1
x : γ
hx : x ∈ s
⊢ ENNReal.ofReal ((1 - κ.rnDerivAux (κ + η) a x) * ((1 - κ.rnDerivAux (κ + η) a x)⁻¹ * κ.rnDerivAux (κ + η) a x)) =
    ENNReal.ofReal (κ.rnDerivAux (κ + η) a x)

pp: α : Type u_1
γ : Type u_2
mα : MeasurableSpace α
mγ : MeasurableSpace γ
κ η : Kernel α γ
hαγ : MeasurableSpace.CountableOrCountablyGenerated α γ
inst✝¹ : IsFiniteKernel κ
inst✝ : IsFiniteKernel η
a : α
s : Set γ
hsm : MeasurableSet s
hs : s ⊆ (κ.mutuallySingularSetSlice η a)ᶜ
this :
  η.withDensity (κ.rnDeriv η) =
    ((κ + η).withDensity fun a x ↦ ↑(1 - κ.rnDerivAux (κ + η) a x).toNNReal).withDensity (κ.rnDeriv η)
hs' : ∀ x ∈ s, κ.rnDerivAux (κ + η) a x < 1
x : γ
hx : x ∈ s
⊢ 0 ≤ 1 - κ.rnDerivAux (κ + η) a x

pp: α : Type u_1
γ : Type u_2
mα : MeasurableSpace α
mγ : MeasurableSpace γ
κ η : Kernel α γ
hαγ : MeasurableSpace.CountableOrCountablyGenerated α γ
inst✝¹ : IsFiniteKernel κ
inst✝ : IsFiniteKernel η
a : α
s : Set γ
hsm : MeasurableSet s
hs : s ⊆ (κ.mutuallySingularSetSlice η a)ᶜ
this :
  η.withDensity (κ.rnDeriv η) =
    ((κ + η).withDensity fun a x ↦ ↑(1 - κ.rnDerivAux (κ + η) a x).toNNReal).withDensity (κ.rnDeriv η)
hs' : ∀ x ∈ s, κ.rnDerivAux (κ + η) a x < 1
x : γ
hx : x ∈ s
⊢ 0 < 1 - κ.rnDerivAux (κ + η) a x

Tactic:
← mul_assoc,

Goal state after:
α : Type u_1
γ : Type u_2
mα : MeasurableSpace α
mγ : MeasurableSpace γ
κ η : Kernel α γ
hαγ : MeasurableSpace.CountableOrCountablyGenerated α γ
inst✝¹ : IsFiniteKernel κ
inst✝ : IsFiniteKernel η
a : α
s : Set γ
hsm : MeasurableSet s
hs : s ⊆ (κ.mutuallySingularSetSlice η a)ᶜ
this :
  η.withDensity (κ.rnDeriv η) =
    ((κ + η).withDensity fun a x ↦ ↑(1 - κ.rnDerivAux (κ + η) a x).toNNReal).withDensity (κ.rnDeriv η)
hs' : ∀ x ∈ s, κ.rnDerivAux (κ + η) a x < 1
x : γ
hx : x ∈ s
⊢ ENNReal.ofReal ((1 - κ.rnDerivAux (κ + η) a x) * (1 - κ.rnDerivAux (κ + η) a x)⁻¹ * κ.rnDerivAux (κ + η) a x) =
    ENNReal.ofReal (κ.rnDerivAux (κ + η) a x)

α : Type u_1
γ : Type u_2
mα : MeasurableSpace α
mγ : MeasurableSpace γ
κ η : Kernel α γ
hαγ : MeasurableSpace.CountableOrCountablyGenerated α γ
inst✝¹ : IsFiniteKernel κ
inst✝ : IsFiniteKernel η
a : α
s : Set γ
hsm : MeasurableSet s
hs : s ⊆ (κ.mutuallySingularSetSlice η a)ᶜ
this :
  η.withDensity (κ.rnDeriv η) =
    ((κ + η).withDensity fun a x ↦ ↑(1 - κ.rnDerivAux (κ + η) a x).toNNReal).withDensity (κ.rnDeriv η)
hs' : ∀ x ∈ s, κ.rnDerivAux (κ + η) a x < 1
x : γ
hx : x ∈ s
⊢ 0 ≤ 1 - κ.rnDerivAux (κ + η) a x

α : Type u_1
γ : Type u_2
mα : MeasurableSpace α
mγ : MeasurableSpace γ
κ η : Kernel α γ
hαγ : MeasurableSpace.CountableOrCountablyGenerated α γ
inst✝¹ : IsFiniteKernel κ
inst✝ : IsFiniteKernel η
a : α
s : Set γ
hsm : MeasurableSet s
hs : s ⊆ (κ.mutuallySingularSetSlice η a)ᶜ
this :
  η.withDensity (κ.rnDeriv η) =
    ((κ + η).withDensity fun a x ↦ ↑(1 - κ.rnDerivAux (κ + η) a x).toNNReal).withDensity (κ.rnDeriv η)
hs' : ∀ x ∈ s, κ.rnDerivAux (κ + η) a x < 1
x : γ
hx : x ∈ s
⊢ 0 < 1 - κ.rnDerivAux (κ + η) a x