Theorem: MeasureTheory.Measure.prod_dirac
File: Mathlib/MeasureTheory/Constructions/Prod/Basic.lean

tactic: rw [← sum_sFiniteSeq μ, prod_sum_left, map_sum measurable_prod_mk_right.aemeasurable]
state_before: α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
⊢ μ.prod (dirac y) = map (fun x => (x, y)) μ
state_after: α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
⊢ (sum fun i => (sFiniteSeq μ i).prod (dirac y)) = sum fun i => map (fun x => (x, y)) (sFiniteSeq μ i)

tactic: congr
state_before: α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
⊢ (sum fun i => (sFiniteSeq μ i).prod (dirac y)) = sum fun i => map (fun x => (x, y)) (sFiniteSeq μ i)
state_after: case e_f
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
⊢ (fun i => (sFiniteSeq μ i).prod (dirac y)) = fun i => map (fun x => (x, y)) (sFiniteSeq μ i)

tactic: ext1 i
state_before: case e_f
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
⊢ (fun i => (sFiniteSeq μ i).prod (dirac y)) = fun i => map (fun x => (x, y)) (sFiniteSeq μ i)
state_after: case e_f.h
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
i : ℕ
⊢ (sFiniteSeq μ i).prod (dirac y) = map (fun x => (x, y)) (sFiniteSeq μ i)

tactic: refine prod_eq fun s t hs ht => ?_
state_before: case e_f.h
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
i : ℕ
⊢ (sFiniteSeq μ i).prod (dirac y) = map (fun x => (x, y)) (sFiniteSeq μ i)
state_after: case e_f.h
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
i : ℕ
s : Set α
t : Set β
hs : MeasurableSet s
ht : MeasurableSet t
⊢ (map (fun x => (x, y)) (sFiniteSeq μ i)) (s ×ˢ t) = (sFiniteSeq μ i) s * (dirac y) t

tactic: simp_rw [map_apply measurable_prod_mk_right (hs.prod ht), mk_preimage_prod_left_eq_if, measure_if,
  dirac_apply' _ ht, ← indicator_mul_right _ fun _ => sFiniteSeq μ i s, Pi.one_apply, mul_one]
state_before: case e_f.h
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MeasurableSpace α'
inst✝⁵ : MeasurableSpace β
inst✝⁴ : MeasurableSpace β'
inst✝³ : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝² : NormedAddCommGroup E
inst✝¹ : SFinite ν
inst✝ : SFinite μ
y : β
i : ℕ
s : Set α
t : Set β
hs : MeasurableSet s
ht : MeasurableSet t
⊢ (map (fun x => (x, y)) (sFiniteSeq μ i)) (s ×ˢ t) = (sFiniteSeq μ i) s * (dirac y) t
state_after: no goals