l3lab/ntp-mathlib huggingface dataset:
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
⊢ ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀

Next tactic:
have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
⊢ ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀

Next tactic:
have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
⊢ ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀

Next tactic:
rw [← dslope_same, ← h0]
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
⊢ ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) =
    (2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z

Next tactic:
congr 1
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  

Proof state:
case e_a
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
⊢ (∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z

Next tactic:
trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · 

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
⊢ (∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)

Next tactic:
have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
⊢ ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)

Next tactic:
refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
w : ℂ
hw : w ∈ sphere c R
h : (w - w₀) ^ 2 = 0
⊢ False

Next tactic:
exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
    

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
h1 : ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)
⊢ (∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)

Next tactic:
have h2 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f z) c R := by
      refine' ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le _
      exact h1.smul (hf.continuousOn.mono (sphere_subset_closedBall.trans hc))
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
    have h2 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f z) c R := by
      

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
h1 : ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)
⊢ CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f z) c R

Next tactic:
refine' ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le _
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
    have h2 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f z) c R := by
      refine' ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le _
      

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
h1 : ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)
⊢ ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹ • f z) (sphere c R)

Next tactic:
exact h1.smul (hf.continuousOn.mono (sphere_subset_closedBall.trans hc))
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
    have h2 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f z) c R := by
      refine' ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le _
      exact h1.smul (hf.continuousOn.mono (sphere_subset_closedBall.trans hc))
    

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
h1 : ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)
h2 : CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f z) c R
⊢ (∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)

Next tactic:
have h3 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f w₀) c R :=
      ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le (h1.smul continuousOn_const)
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
    have h2 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f z) c R := by
      refine' ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le _
      exact h1.smul (hf.continuousOn.mono (sphere_subset_closedBall.trans hc))
    have h3 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f w₀) c R :=
      ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le (h1.smul continuousOn_const)
    

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
h1 : ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)
h2 : CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f z) c R
h3 : CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f w₀) c R
⊢ (∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = ∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)

Next tactic:
have h4 : (∮ z : ℂ in C(c, R), ((z - w₀) ^ 2)⁻¹) = 0 := by
      simpa using circleIntegral.integral_sub_zpow_of_ne (by decide : (-2 : ℤ) ≠ -1) c w₀ R
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
    have h2 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f z) c R := by
      refine' ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le _
      exact h1.smul (hf.continuousOn.mono (sphere_subset_closedBall.trans hc))
    have h3 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f w₀) c R :=
      ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le (h1.smul continuousOn_const)
    have h4 : (∮ z : ℂ in C(c, R), ((z - w₀) ^ 2)⁻¹) = 0 := by
      

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
h1 : ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)
h2 : CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f z) c R
h3 : CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f w₀) c R
⊢ (∮ (z : ℂ) in C(c, R), ((z - w₀) ^ 2)⁻¹) = 0

Next tactic:
simpa using circleIntegral.integral_sub_zpow_of_ne (by decide : (-2 : ℤ) ≠ -1) c w₀ R
/-- The Cauchy formula for the derivative of a holomorphic function. -/
theorem two_pi_I_inv_smul_circleIntegral_sub_sq_inv_smul_of_differentiable {U : Set ℂ}
    (hU : IsOpen U) {c w₀ : ℂ} {R : ℝ} {f : ℂ → E} (hc : closedBall c R ⊆ U)
    (hf : DifferentiableOn ℂ f U) (hw₀ : w₀ ∈ ball c R) :
    ((2 * π * I : ℂ)⁻¹ • ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • f z) = deriv f w₀ := by
  -- We apply the removable singularity theorem and the Cauchy formula to `dslope f w₀`
  have hf' : DifferentiableOn ℂ (dslope f w₀) U :=
    (differentiableOn_dslope (hU.mem_nhds ((ball_subset_closedBall.trans hc) hw₀))).mpr hf
  have h0 := (hf'.diffContOnCl_ball hc).two_pi_i_inv_smul_circleIntegral_sub_inv_smul hw₀
  rw [← dslope_same, ← h0]
  congr 1
  trans ∮ z in C(c, R), ((z - w₀) ^ 2)⁻¹ • (f z - f w₀)
  · have h1 : ContinuousOn (fun z : ℂ => ((z - w₀) ^ 2)⁻¹) (sphere c R) := by
      refine' ((continuous_id'.sub continuous_const).pow 2).continuousOn.inv₀ fun w hw h => _
      exact sphere_disjoint_ball.ne_of_mem hw hw₀ (sub_eq_zero.mp (sq_eq_zero_iff.mp h))
    have h2 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f z) c R := by
      refine' ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le _
      exact h1.smul (hf.continuousOn.mono (sphere_subset_closedBall.trans hc))
    have h3 : CircleIntegrable (fun z : ℂ => ((z - w₀) ^ 2)⁻¹ • f w₀) c R :=
      ContinuousOn.circleIntegrable (pos_of_mem_ball hw₀).le (h1.smul continuousOn_const)
    have h4 : (∮ z : ℂ in C(c, R), ((z - w₀) ^ 2)⁻¹) = 0 := by
      simpa using circleIntegral.integral_sub_zpow_of_ne (by 

Proof state:
E : Type u
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace ℂ E
inst✝ : CompleteSpace E
U : Set ℂ
hU : IsOpen U
c w₀ : ℂ
R : ℝ
f : ℂ → E
hc : closedBall c R ⊆ U
hf : DifferentiableOn ℂ f U
hw₀ : w₀ ∈ ball c R
hf' : DifferentiableOn ℂ (dslope f w₀) U
h0 : ((2 * ↑π * I)⁻¹ • ∮ (z : ℂ) in C(c, R), (z - w₀)⁻¹ • dslope f w₀ z) = dslope f w₀ w₀
h1 : ContinuousOn (fun z => ((z - w₀) ^ 2)⁻¹) (sphere c R)
h2 : CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f z) c R
h3 : CircleIntegrable (fun z => ((z - w₀) ^ 2)⁻¹ • f w₀) c R
⊢ -2 ≠ -1

Next tactic:
decide