Theorem: Complex.two_pi_I_inv_smul_circleIntegral_sub_inv_smul_of_differentiable_on_off_countable
File: Mathlib/Analysis/Complex/CauchyIntegral.lean

Proof steps:
state_before: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
⊢ ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w)⁻¹ • f z) = f w
state_after: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
⊢ ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w)⁻¹ • f z) = f w
tactic: have hR : 0 < R := dist_nonneg.trans_lt hw
state_before: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
⊢ ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w)⁻¹ • f z) = f w
state_after: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
⊢ w ∈ closure (ball c R \ s)
tactic: suffices w ∈ closure (ball c R \ s) by
    lift R to ℝ≥0 using hR.le
    have A : ContinuousAt (fun w => (2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), (z - w)⁻¹ • f z) w := by
      have := hasFPowerSeriesOn_cauchy_integral
        ((hc.mono sphere_subset_closedBall).circleIntegrable R.coe_nonneg) hR
      refine this.continuousOn.continuousAt (EMetric.isOpen_ball.mem_nhds ?_)
      rwa [Metric.emetric_ball_nnreal]
    have B : ContinuousAt f w := hc.continuousAt (closedBall_mem_nhds_of_mem hw)
    refine tendsto_nhds_unique_of_frequently_eq A B ((mem_closure_iff_frequently.1 this).mono ?_)
    intro z hz
    rw [circleIntegral_sub_inv_smul_of_differentiable_on_off_countable_aux hs hz hc hd,
      inv_smul_smul₀]
    simp [Real.pi_ne_zero, I_ne_zero]
state_before: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
⊢ w ∈ closure (ball c R \ s)
state_after: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
⊢ (t ∩ (ball c R \ s)).Nonempty
tactic: refine mem_closure_iff_nhds.2 fun t ht => ?_
state_before: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
⊢ (t ∩ (ball c R \ s)).Nonempty
state_after: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
⊢ (t ∩ (ball c R \ s)).Nonempty
tactic: set g : ℝ → ℂ := fun x => w + ofReal x
state_before: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
⊢ (t ∩ (ball c R \ s)).Nonempty
state_after: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
this : Tendsto g (𝓝 0) (𝓝 w)
⊢ (t ∩ (ball c R \ s)).Nonempty
tactic: have : Tendsto g (𝓝 0) (𝓝 w) :=
    (continuous_const.add continuous_ofReal).tendsto' 0 w (add_zero _)
state_before: E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
this : Tendsto g (𝓝 0) (𝓝 w)
⊢ (t ∩ (ball c R \ s)).Nonempty
state_after: case intro.intro.intro
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
this : Tendsto g (𝓝 0) (𝓝 w)
l u : ℝ
hlu₀ : 0 ∈ Ioo l u
hlu_sub : Ioo l u ⊆ g ⁻¹' (t ∩ ball c R)
⊢ (t ∩ (ball c R \ s)).Nonempty
tactic: rcases mem_nhds_iff_exists_Ioo_subset.1 (this <| inter_mem ht <| isOpen_ball.mem_nhds hw) with
    ⟨l, u, hlu₀, hlu_sub⟩
state_before: case intro.intro.intro
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
this : Tendsto g (𝓝 0) (𝓝 w)
l u : ℝ
hlu₀ : 0 ∈ Ioo l u
hlu_sub : Ioo l u ⊆ g ⁻¹' (t ∩ ball c R)
⊢ (t ∩ (ball c R \ s)).Nonempty
state_after: case intro.intro.intro.intro
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
this : Tendsto g (𝓝 0) (𝓝 w)
l u : ℝ
hlu₀ : 0 ∈ Ioo l u
hlu_sub : Ioo l u ⊆ g ⁻¹' (t ∩ ball c R)
x : ℝ
hx : x ∈ Ioo l u \ g ⁻¹' s
⊢ (t ∩ (ball c R \ s)).Nonempty
tactic: obtain ⟨x, hx⟩ : (Ioo l u \ g ⁻¹' s).Nonempty := by
    refine nonempty_diff.2 fun hsub => ?_
    have : (Ioo l u).Countable :=
      (hs.preimage ((add_right_injective w).comp ofReal_injective)).mono hsub
    rw [← Cardinal.le_aleph0_iff_set_countable, Cardinal.mk_Ioo_real (hlu₀.1.trans hlu₀.2)] at this
    exact this.not_lt Cardinal.aleph0_lt_continuum
state_before: case intro.intro.intro.intro
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
R : ℝ
c w : ℂ
f : ℂ → E
s : Set ℂ
hs : s.Countable
hw : w ∈ ball c R
hc : ContinuousOn f (closedBall c R)
hd : ∀ x ∈ ball c R \ s, DifferentiableAt ℂ f x
hR : 0 < R
t : Set ℂ
ht : t ∈ 𝓝 w
g : ℝ → ℂ := fun x => w + ofReal x
this : Tendsto g (𝓝 0) (𝓝 w)
l u : ℝ
hlu₀ : 0 ∈ Ioo l u
hlu_sub : Ioo l u ⊆ g ⁻¹' (t ∩ ball c R)
x : ℝ
hx : x ∈ Ioo l u \ g ⁻¹' s
⊢ (t ∩ (ball c R \ s)).Nonempty
state_after: no goals
tactic: exact ⟨g x, (hlu_sub hx.1).1, (hlu_sub hx.1).2, hx.2⟩