-- Mathlib/Analysis/Complex/Hadamard.lean
lemma norm_le_interpStrip_of_mem_verticalClosedStrip_eps (ε : ℝ) (hε : ε > 0) (z : ℂ)
    (hB : BddAbove ((norm ∘ f) '' verticalClosedStrip 0 1))
    (hd : DiffContOnCl ℂ f (verticalStrip 0 1)) (hz : z ∈ verticalClosedStrip 0 1) :
    ‖f z‖ ≤  ‖((ε + sSupNormIm f 0) ^ (1-z) * (ε + sSupNormIm f 1) ^ z : ℂ)‖

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ 0 < (ε + sSupNormIm f 0) ^ (1 - z.re)

Tactic:
simp only [Real.rpow_pos_of_pos (sSupNormIm_eps_pos f hε _) (1-z.re)]

Result:
no goals

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ ‖f z‖ ≤ (ε + sSupNormIm f 0) ^ (1 - z.re) * (ε + sSupNormIm f 1) ^ z.re

Tactic:
rw [← mul_inv_le_iff₀', ← one_mul (((ε + sSupNormIm f 1) ^ z.re)), ← mul_inv_le_iff₀,
  ← Real.rpow_neg_one, ← Real.rpow_neg_one]

Result:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ ‖f z‖ * ((ε + sSupNormIm f 0) ^ (1 - z.re)) ^ (-1) * ((ε + sSupNormIm f 1) ^ z.re) ^ (-1) ≤ 1

E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ 0 < (ε + sSupNormIm f 1) ^ z.re

E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ 0 < (ε + sSupNormIm f 0) ^ (1 - z.re)

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ ‖f z‖ ≤ ‖(↑ε + ↑(sSupNormIm f 0)) ^ (1 - z) * (↑ε + ↑(sSupNormIm f 1)) ^ z‖

Tactic:
simp only [F, norm_invInterpStrip _ _ hε, norm_smul, norm_mul,
  ← ofReal_add, norm_cpow_eq_rpow_re_of_pos (sSupNormIm_eps_pos f hε _) _, sub_re, one_re]

Result:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ ‖f z‖ ≤ (ε + sSupNormIm f 0) ^ (1 - z.re) * (ε + sSupNormIm f 1) ^ z.re

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ ‖f z‖ * ((ε + sSupNormIm f 0) ^ (z.re - 1) * (ε + sSupNormIm f 1) ^ (-z.re)) ≤ 1

Tactic:
simpa [F, norm_invInterpStrip _ _ hε, norm_smul, mul_comm] using
  norm_mul_invInterpStrip_le_one_of_mem_verticalClosedStrip f ε hε z hd hB hz

Result:
no goals

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ ‖f z‖ * ((ε + sSupNormIm f 0) ^ (1 - z.re)) ^ (-1) * ((ε + sSupNormIm f 1) ^ z.re) ^ (-1) ≤ 1

Tactic:
simp only [← Real.rpow_mul (le_of_lt (sSupNormIm_eps_pos f hε _)),
mul_neg, mul_one, neg_sub, mul_assoc]

Result:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ ‖f z‖ * ((ε + sSupNormIm f 0) ^ (z.re - 1) * (ε + sSupNormIm f 1) ^ (-z.re)) ≤ 1

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
f : ℂ → E
inst✝ : NormedSpace ℂ E
ε : ℝ
hε : ε > 0
z : ℂ
hB : BddAbove (norm ∘ f '' verticalClosedStrip 0 1)
hd : DiffContOnCl ℂ f (verticalStrip 0 1)
hz : z ∈ verticalClosedStrip 0 1
⊢ 0 < (ε + sSupNormIm f 1) ^ z.re

Tactic:
simp only [Real.rpow_pos_of_pos (sSupNormIm_eps_pos f hε _) z.re]

Result:
no goals