Theorem: LipschitzOnWith.ae_differentiableWithinAt_of_mem_pi
File: Mathlib/Analysis/Calculus/Rademacher.lean

Proof steps:
state_before: E : Type u_1
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace ℝ E
inst✝⁷ : FiniteDimensional ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
F : Type u_2
inst✝⁴ : NormedAddCommGroup F
inst✝³ : NormedSpace ℝ F
C D : ℝ≥0
f✝ g : E → ℝ
s✝ : Set E
μ : Measure E
inst✝² : μ.IsAddHaarMeasure
inst✝¹ : FiniteDimensional ℝ F
ι : Type u_3
inst✝ : Fintype ι
f : E → ι → ℝ
s : Set E
hf : LipschitzOnWith C f s
⊢ ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ f s x
state_after: E : Type u_1
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace ℝ E
inst✝⁷ : FiniteDimensional ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
F : Type u_2
inst✝⁴ : NormedAddCommGroup F
inst✝³ : NormedSpace ℝ F
C D : ℝ≥0
f✝ g : E → ℝ
s✝ : Set E
μ : Measure E
inst✝² : μ.IsAddHaarMeasure
inst✝¹ : FiniteDimensional ℝ F
ι : Type u_3
inst✝ : Fintype ι
f : E → ι → ℝ
s : Set E
hf : LipschitzOnWith C f s
A : ∀ (i : ι), LipschitzWith 1 fun x => x i
⊢ ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ f s x
tactic: have A : ∀ i : ι, LipschitzWith 1 (fun x : ι → ℝ ↦ x i) := fun i => LipschitzWith.eval i
state_before: E : Type u_1
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace ℝ E
inst✝⁷ : FiniteDimensional ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
F : Type u_2
inst✝⁴ : NormedAddCommGroup F
inst✝³ : NormedSpace ℝ F
C D : ℝ≥0
f✝ g : E → ℝ
s✝ : Set E
μ : Measure E
inst✝² : μ.IsAddHaarMeasure
inst✝¹ : FiniteDimensional ℝ F
ι : Type u_3
inst✝ : Fintype ι
f : E → ι → ℝ
s : Set E
hf : LipschitzOnWith C f s
A : ∀ (i : ι), LipschitzWith 1 fun x => x i
⊢ ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ f s x
state_after: E : Type u_1
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace ℝ E
inst✝⁷ : FiniteDimensional ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
F : Type u_2
inst✝⁴ : NormedAddCommGroup F
inst✝³ : NormedSpace ℝ F
C D : ℝ≥0
f✝ g : E → ℝ
s✝ : Set E
μ : Measure E
inst✝² : μ.IsAddHaarMeasure
inst✝¹ : FiniteDimensional ℝ F
ι : Type u_3
inst✝ : Fintype ι
f : E → ι → ℝ
s : Set E
hf : LipschitzOnWith C f s
A : ∀ (i : ι), LipschitzWith 1 fun x => x i
this : ∀ (i : ι), ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ (fun x => f x i) s x
⊢ ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ f s x
tactic: have : ∀ i : ι, ∀ᵐ x ∂μ, x ∈ s → DifferentiableWithinAt ℝ (fun x : E ↦ f x i) s x := fun i ↦ by
    apply ae_differentiableWithinAt_of_mem_of_real
    exact LipschitzWith.comp_lipschitzOnWith (A i) hf
state_before: E : Type u_1
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace ℝ E
inst✝⁷ : FiniteDimensional ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
F : Type u_2
inst✝⁴ : NormedAddCommGroup F
inst✝³ : NormedSpace ℝ F
C D : ℝ≥0
f✝ g : E → ℝ
s✝ : Set E
μ : Measure E
inst✝² : μ.IsAddHaarMeasure
inst✝¹ : FiniteDimensional ℝ F
ι : Type u_3
inst✝ : Fintype ι
f : E → ι → ℝ
s : Set E
hf : LipschitzOnWith C f s
A : ∀ (i : ι), LipschitzWith 1 fun x => x i
this : ∀ (i : ι), ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ (fun x => f x i) s x
⊢ ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ f s x
state_after: case h
E : Type u_1
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace ℝ E
inst✝⁷ : FiniteDimensional ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
F : Type u_2
inst✝⁴ : NormedAddCommGroup F
inst✝³ : NormedSpace ℝ F
C D : ℝ≥0
f✝ g : E → ℝ
s✝ : Set E
μ : Measure E
inst✝² : μ.IsAddHaarMeasure
inst✝¹ : FiniteDimensional ℝ F
ι : Type u_3
inst✝ : Fintype ι
f : E → ι → ℝ
s : Set E
hf : LipschitzOnWith C f s
A : ∀ (i : ι), LipschitzWith 1 fun x => x i
this : ∀ (i : ι), ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ (fun x => f x i) s x
x : E
hx : ∀ (i : ι), x ∈ s → DifferentiableWithinAt ℝ (fun x => f x i) s x
xs : x ∈ s
⊢ DifferentiableWithinAt ℝ f s x
tactic: filter_upwards [ae_all_iff.2 this] with x hx xs
state_before: case h
E : Type u_1
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace ℝ E
inst✝⁷ : FiniteDimensional ℝ E
inst✝⁶ : MeasurableSpace E
inst✝⁵ : BorelSpace E
F : Type u_2
inst✝⁴ : NormedAddCommGroup F
inst✝³ : NormedSpace ℝ F
C D : ℝ≥0
f✝ g : E → ℝ
s✝ : Set E
μ : Measure E
inst✝² : μ.IsAddHaarMeasure
inst✝¹ : FiniteDimensional ℝ F
ι : Type u_3
inst✝ : Fintype ι
f : E → ι → ℝ
s : Set E
hf : LipschitzOnWith C f s
A : ∀ (i : ι), LipschitzWith 1 fun x => x i
this : ∀ (i : ι), ∀ᵐ (x : E) ∂μ, x ∈ s → DifferentiableWithinAt ℝ (fun x => f x i) s x
x : E
hx : ∀ (i : ι), x ∈ s → DifferentiableWithinAt ℝ (fun x => f x i) s x
xs : x ∈ s
⊢ DifferentiableWithinAt ℝ f s x
state_after: no goals
tactic: exact differentiableWithinAt_pi.2 (fun i ↦ hx i xs)