Module: Mathlib.Analysis.Complex.Schwarz

Goal state before:
pp: f : ℂ → ℂ
c z : ℂ
R₁ R₂ : ℝ
n : ℕ
hd : DifferentiableOn ℂ f (ball c R₁)
h_maps : MapsTo f (ball c R₁) (closedBall (f c) R₂)
hn : (fun x ↦ f x - f c) =o[𝓝 c] fun w ↦ (w - c) ^ n
hz : ‖z - c‖ < R₁
hR₁ : 0 < R₁
this :
  ∀ {R₁ : ℝ},
    DifferentiableOn ℂ f (ball c R₁) →
      MapsTo f (ball c R₁) (closedBall (f c) R₂) →
        z ∈ ball c R₁ →
          0 < R₁ →
            DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂) →
              ‖f z - f c‖ ≤ R₂ * (‖z - c‖ / R₁) ^ (n + 1)
hd' : ¬(DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂))
r : ℝ
hzr : ‖z - c‖ < r
hrR₁ : r < R₁
⊢ ‖f z - f c‖ ≤ R₂ * (‖z - c‖ / r) ^ (n + 1)

Tactic:
apply this

Goal state after:
case hd
f : ℂ → ℂ
c z : ℂ
R₁ R₂ : ℝ
n : ℕ
hd : DifferentiableOn ℂ f (ball c R₁)
h_maps : MapsTo f (ball c R₁) (closedBall (f c) R₂)
hn : (fun x ↦ f x - f c) =o[𝓝 c] fun w ↦ (w - c) ^ n
hz : ‖z - c‖ < R₁
hR₁ : 0 < R₁
this :
  ∀ {R₁ : ℝ},
    DifferentiableOn ℂ f (ball c R₁) →
      MapsTo f (ball c R₁) (closedBall (f c) R₂) →
        z ∈ ball c R₁ →
          0 < R₁ →
            DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂) →
              ‖f z - f c‖ ≤ R₂ * (‖z - c‖ / R₁) ^ (n + 1)
hd' : ¬(DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂))
r : ℝ
hzr : ‖z - c‖ < r
hrR₁ : r < R₁
⊢ DifferentiableOn ℂ f (ball c r)

case h_maps
f : ℂ → ℂ
c z : ℂ
R₁ R₂ : ℝ
n : ℕ
hd : DifferentiableOn ℂ f (ball c R₁)
h_maps : MapsTo f (ball c R₁) (closedBall (f c) R₂)
hn : (fun x ↦ f x - f c) =o[𝓝 c] fun w ↦ (w - c) ^ n
hz : ‖z - c‖ < R₁
hR₁ : 0 < R₁
this :
  ∀ {R₁ : ℝ},
    DifferentiableOn ℂ f (ball c R₁) →
      MapsTo f (ball c R₁) (closedBall (f c) R₂) →
        z ∈ ball c R₁ →
          0 < R₁ →
            DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂) →
              ‖f z - f c‖ ≤ R₂ * (‖z - c‖ / R₁) ^ (n + 1)
hd' : ¬(DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂))
r : ℝ
hzr : ‖z - c‖ < r
hrR₁ : r < R₁
⊢ MapsTo f (ball c r) (closedBall (f c) R₂)

case hz
f : ℂ → ℂ
c z : ℂ
R₁ R₂ : ℝ
n : ℕ
hd : DifferentiableOn ℂ f (ball c R₁)
h_maps : MapsTo f (ball c R₁) (closedBall (f c) R₂)
hn : (fun x ↦ f x - f c) =o[𝓝 c] fun w ↦ (w - c) ^ n
hz : ‖z - c‖ < R₁
hR₁ : 0 < R₁
this :
  ∀ {R₁ : ℝ},
    DifferentiableOn ℂ f (ball c R₁) →
      MapsTo f (ball c R₁) (closedBall (f c) R₂) →
        z ∈ ball c R₁ →
          0 < R₁ →
            DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂) →
              ‖f z - f c‖ ≤ R₂ * (‖z - c‖ / R₁) ^ (n + 1)
hd' : ¬(DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂))
r : ℝ
hzr : ‖z - c‖ < r
hrR₁ : r < R₁
⊢ z ∈ ball c r

case hR₁
f : ℂ → ℂ
c z : ℂ
R₁ R₂ : ℝ
n : ℕ
hd : DifferentiableOn ℂ f (ball c R₁)
h_maps : MapsTo f (ball c R₁) (closedBall (f c) R₂)
hn : (fun x ↦ f x - f c) =o[𝓝 c] fun w ↦ (w - c) ^ n
hz : ‖z - c‖ < R₁
hR₁ : 0 < R₁
this :
  ∀ {R₁ : ℝ},
    DifferentiableOn ℂ f (ball c R₁) →
      MapsTo f (ball c R₁) (closedBall (f c) R₂) →
        z ∈ ball c R₁ →
          0 < R₁ →
            DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂) →
              ‖f z - f c‖ ≤ R₂ * (‖z - c‖ / R₁) ^ (n + 1)
hd' : ¬(DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂))
r : ℝ
hzr : ‖z - c‖ < r
hrR₁ : r < R₁
⊢ 0 < r

case hd'
f : ℂ → ℂ
c z : ℂ
R₁ R₂ : ℝ
n : ℕ
hd : DifferentiableOn ℂ f (ball c R₁)
h_maps : MapsTo f (ball c R₁) (closedBall (f c) R₂)
hn : (fun x ↦ f x - f c) =o[𝓝 c] fun w ↦ (w - c) ^ n
hz : ‖z - c‖ < R₁
hR₁ : 0 < R₁
this :
  ∀ {R₁ : ℝ},
    DifferentiableOn ℂ f (ball c R₁) →
      MapsTo f (ball c R₁) (closedBall (f c) R₂) →
        z ∈ ball c R₁ →
          0 < R₁ →
            DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂) →
              ‖f z - f c‖ ≤ R₂ * (‖z - c‖ / R₁) ^ (n + 1)
hd' : ¬(DifferentiableOn ℂ f (closedBall c R₁) ∧ MapsTo f (closedBall c R₁) (closedBall (f c) R₂))
r : ℝ
hzr : ‖z - c‖ < r
hrR₁ : r < R₁
⊢ DifferentiableOn ℂ f (closedBall c r) ∧ MapsTo f (closedBall c r) (closedBall (f c) R₂)