l3lab/ntp-mathlib huggingface dataset:
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f : ℂ → E` be a function such that

* `f` is differentiable in the open right half-plane and is continuous on its closure;
* `‖f z‖` is bounded from above by `A * exp(B * (abs z) ^ c)` on the open right half-plane
  for some `c < 2`;
* `‖f z‖` is bounded from above by a constant on the imaginary axis;
* `f x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x‖` tends to zero as `x → ∞`.

Then `f` is equal to zero on the closed right half-plane. -/
theorem eq_zero_on_right_half_plane_of_superexponential_decay (hd : DiffContOnCl ℂ f {z | 0 < z.re})
    (hexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x‖) (him : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) :
    EqOn f 0 {z : ℂ | 0 ≤ z.re} := by
  rcases him with ⟨C, hC⟩
  -- Due to continuity, it suffices to prove the equality on the open right half-plane.
  suffices ∀ z : ℂ, 0 < z.re → f z = 0 by
    simpa only [closure_setOf_lt_re] using
      EqOn.of_subset_closure this hd.continuousOn continuousOn_const subset_closure Subset.rfl
  -- Consider $g_n(z)=e^{nz}f(z)$.
  set g : ℕ → ℂ → E := fun (n : ℕ) (z : ℂ) => exp z ^ n • f z
  have hg : ∀ n z, ‖g n z‖ = expR z.re ^ n * ‖f z‖ := fun n z ↦ by
    simp only [norm_smul, norm_eq_abs, Complex.abs_pow, abs_exp]
  intro z hz
  -- Since `e^{nz} → ∞` as `n → ∞`, it suffices to show that each `g_n` is bounded from above by `C`
  suffices H : ∀ n : ℕ, ‖g n z‖ ≤ C
  · contrapose! H
    simp only [hg]
    exact (((tendsto_pow_atTop_atTop_of_one_lt (Real.one_lt_exp_iff.2 hz)).atTop_mul
      (norm_pos_iff.2 H) tendsto_const_nhds).eventually (eventually_gt_atTop C)).exists
  intro n
  -- This estimate follows from the Phragmen-Lindelöf principle in the right half-plane.
  refine' right_half_plane_of_tendsto_zero_on_real ((differentiable_exp.pow n).diffContOnCl.smul hd)
    _ _ (fun y => _) hz.le
  · rcases hexp with ⟨c, hc, B, hO⟩
    refine' ⟨max c 1, max_lt hc one_lt_two, n + max B 0, .of_norm_left _⟩
    simp only [hg]
    refine' ((isBigO_refl (fun z : ℂ => expR z.re ^ n) _).mul hO.norm_left).trans (.of_bound 1 _)
    filter_upwards [(eventually_cobounded_le_norm 1).filter_mono inf_le_left] with z hz
    simp only [← Real.exp_nat_mul, ← Real.exp_add, Real.norm_eq_abs, Real.abs_exp, add_mul, one_mul]
    

Proof state:
case h
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C✝ : ℝ
f g✝ : ℂ → E
z✝¹ : ℂ
hd : DiffContOnCl ℂ f {z | 0 < z.re}
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x‖
C : ℝ
hC : ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
g : ℕ → ℂ → E := fun n z => cexp z ^ n • f z
hg : ∀ (n : ℕ) (z : ℂ), ‖g n z‖ = expR z.re ^ n * ‖f z‖
z✝ : ℂ
hz✝ : 0 < z✝.re
n : ℕ
c : ℝ
hc : c < 2
B : ℝ
hO : f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
z : ℂ
hz : 1 ≤ ‖z‖
⊢ expR (↑n * z.re + B * Complex.abs z ^ c) ≤ expR (↑n * Complex.abs z ^ max c 1 + max B 0 * Complex.abs z ^ max c 1)

Next tactic:
gcongr
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f : ℂ → E` be a function such that

* `f` is differentiable in the open right half-plane and is continuous on its closure;
* `‖f z‖` is bounded from above by `A * exp(B * (abs z) ^ c)` on the open right half-plane
  for some `c < 2`;
* `‖f z‖` is bounded from above by a constant on the imaginary axis;
* `f x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x‖` tends to zero as `x → ∞`.

Then `f` is equal to zero on the closed right half-plane. -/
theorem eq_zero_on_right_half_plane_of_superexponential_decay (hd : DiffContOnCl ℂ f {z | 0 < z.re})
    (hexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x‖) (him : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) :
    EqOn f 0 {z : ℂ | 0 ≤ z.re} := by
  rcases him with ⟨C, hC⟩
  -- Due to continuity, it suffices to prove the equality on the open right half-plane.
  suffices ∀ z : ℂ, 0 < z.re → f z = 0 by
    simpa only [closure_setOf_lt_re] using
      EqOn.of_subset_closure this hd.continuousOn continuousOn_const subset_closure Subset.rfl
  -- Consider $g_n(z)=e^{nz}f(z)$.
  set g : ℕ → ℂ → E := fun (n : ℕ) (z : ℂ) => exp z ^ n • f z
  have hg : ∀ n z, ‖g n z‖ = expR z.re ^ n * ‖f z‖ := fun n z ↦ by
    simp only [norm_smul, norm_eq_abs, Complex.abs_pow, abs_exp]
  intro z hz
  -- Since `e^{nz} → ∞` as `n → ∞`, it suffices to show that each `g_n` is bounded from above by `C`
  suffices H : ∀ n : ℕ, ‖g n z‖ ≤ C
  · contrapose! H
    simp only [hg]
    exact (((tendsto_pow_atTop_atTop_of_one_lt (Real.one_lt_exp_iff.2 hz)).atTop_mul
      (norm_pos_iff.2 H) tendsto_const_nhds).eventually (eventually_gt_atTop C)).exists
  intro n
  -- This estimate follows from the Phragmen-Lindelöf principle in the right half-plane.
  refine' right_half_plane_of_tendsto_zero_on_real ((differentiable_exp.pow n).diffContOnCl.smul hd)
    _ _ (fun y => _) hz.le
  · rcases hexp with ⟨c, hc, B, hO⟩
    refine' ⟨max c 1, max_lt hc one_lt_two, n + max B 0, .of_norm_left _⟩
    simp only [hg]
    refine' ((isBigO_refl (fun z : ℂ => expR z.re ^ n) _).mul hO.norm_left).trans (.of_bound 1 _)
    filter_upwards [(eventually_cobounded_le_norm 1).filter_mono inf_le_left] with z hz
    simp only [← Real.exp_nat_mul, ← Real.exp_add, Real.norm_eq_abs, Real.abs_exp, add_mul, one_mul]
    gcongr
    · 

Proof state:
case h.h.h₁.h
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C✝ : ℝ
f g✝ : ℂ → E
z✝¹ : ℂ
hd : DiffContOnCl ℂ f {z | 0 < z.re}
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x‖
C : ℝ
hC : ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
g : ℕ → ℂ → E := fun n z => cexp z ^ n • f z
hg : ∀ (n : ℕ) (z : ℂ), ‖g n z‖ = expR z.re ^ n * ‖f z‖
z✝ : ℂ
hz✝ : 0 < z✝.re
n : ℕ
c : ℝ
hc : c < 2
B : ℝ
hO : f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
z : ℂ
hz : 1 ≤ ‖z‖
⊢ z.re ≤ Complex.abs z ^ max c 1

Next tactic:
calc
        z.re ≤ abs z := re_le_abs _
        _ = abs z ^ (1 : ℝ) := (Real.rpow_one _).symm
        _ ≤ abs z ^ max c 1 := Real.rpow_le_rpow_of_exponent_le hz (le_max_right _ _)
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hfexp : ∃ c < 2, ∃ B, f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hgexp : ∃ c < 2, ∃ B, g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
⊢ EqOn f g {z | 0 ≤ z.re}

Next tactic:
suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hfexp : ∃ c < 2, ∃ B, f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hgexp : ∃ c < 2, ∃ B, g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
this : EqOn (f - g) 0 {z | 0 ≤ z.re}
⊢ EqOn f g {z | 0 ≤ z.re}

Next tactic:
simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
  

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hfexp : ∃ c < 2, ∃ B, f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hgexp : ∃ c < 2, ∃ B, g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
⊢ EqOn (f - g) 0 {z | 0 ≤ z.re}

Next tactic:
refine' eq_zero_on_right_half_plane_of_superexponential_decay (hfd.sub hgd) _ hre _
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
  refine' eq_zero_on_right_half_plane_of_superexponential_decay (hfd.sub hgd) _ hre _
  · 

Proof state:
case refine'_1
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hfexp : ∃ c < 2, ∃ B, f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hgexp : ∃ c < 2, ∃ B, g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
⊢ ∃ c < 2, ∃ B, (f - g) =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * Complex.abs z ^ c)

Next tactic:
set l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z : ℂ | 0 < z.re}
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
  refine' eq_zero_on_right_half_plane_of_superexponential_decay (hfd.sub hgd) _ hre _
  · set l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z : ℂ | 0 < z.re}
    

Proof state:
case refine'_1
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}
hfexp : ∃ c < 2, ∃ B, f =O[l] fun z => expR (B * Complex.abs z ^ c)
hgexp : ∃ c < 2, ∃ B, g =O[l] fun z => expR (B * Complex.abs z ^ c)
⊢ ∃ c < 2, ∃ B, (f - g) =O[l] fun z => expR (B * Complex.abs z ^ c)

Next tactic:
suffices ∀ {c₁ c₂ B₁ B₂ : ℝ}, c₁ ≤ c₂ → B₁ ≤ B₂ → 0 ≤ B₂ →
        (fun z => expR (B₁ * abs z ^ c₁)) =O[l] fun z => expR (B₂ * abs z ^ c₂) by
      rcases hfexp with ⟨cf, hcf, Bf, hOf⟩; rcases hgexp with ⟨cg, hcg, Bg, hOg⟩
      refine' ⟨max cf cg, max_lt hcf hcg, max 0 (max Bf Bg), _⟩
      refine' .sub (hOf.trans <| this _ _ _) (hOg.trans <| this _ _ _) <;> simp
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
  refine' eq_zero_on_right_half_plane_of_superexponential_decay (hfd.sub hgd) _ hre _
  · set l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z : ℂ | 0 < z.re}
    suffices ∀ {c₁ c₂ B₁ B₂ : ℝ}, c₁ ≤ c₂ → B₁ ≤ B₂ → 0 ≤ B₂ →
        (fun z => expR (B₁ * abs z ^ c₁)) =O[l] fun z => expR (B₂ * abs z ^ c₂) by
      

Proof state:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}
hfexp : ∃ c < 2, ∃ B, f =O[l] fun z => expR (B * Complex.abs z ^ c)
hgexp : ∃ c < 2, ∃ B, g =O[l] fun z => expR (B * Complex.abs z ^ c)
this :
  ∀ {c₁ c₂ B₁ B₂ : ℝ},
    c₁ ≤ c₂ → B₁ ≤ B₂ → 0 ≤ B₂ → (fun z => expR (B₁ * Complex.abs z ^ c₁)) =O[l] fun z => expR (B₂ * Complex.abs z ^ c₂)
⊢ ∃ c < 2, ∃ B, (f - g) =O[l] fun z => expR (B * Complex.abs z ^ c)

Next tactic:
rcases hfexp with ⟨cf, hcf, Bf, hOf⟩
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
  refine' eq_zero_on_right_half_plane_of_superexponential_decay (hfd.sub hgd) _ hre _
  · set l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z : ℂ | 0 < z.re}
    suffices ∀ {c₁ c₂ B₁ B₂ : ℝ}, c₁ ≤ c₂ → B₁ ≤ B₂ → 0 ≤ B₂ →
        (fun z => expR (B₁ * abs z ^ c₁)) =O[l] fun z => expR (B₂ * abs z ^ c₂) by
      rcases hfexp with ⟨cf, hcf, Bf, hOf⟩; 

Proof state:
case intro.intro.intro
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}
hgexp : ∃ c < 2, ∃ B, g =O[l] fun z => expR (B * Complex.abs z ^ c)
this :
  ∀ {c₁ c₂ B₁ B₂ : ℝ},
    c₁ ≤ c₂ → B₁ ≤ B₂ → 0 ≤ B₂ → (fun z => expR (B₁ * Complex.abs z ^ c₁)) =O[l] fun z => expR (B₂ * Complex.abs z ^ c₂)
cf : ℝ
hcf : cf < 2
Bf : ℝ
hOf : f =O[l] fun z => expR (Bf * Complex.abs z ^ cf)
⊢ ∃ c < 2, ∃ B, (f - g) =O[l] fun z => expR (B * Complex.abs z ^ c)

Next tactic:
rcases hgexp with ⟨cg, hcg, Bg, hOg⟩
/-- **Phragmen-Lindelöf principle** in the right half-plane. Let `f g : ℂ → E` be functions such
that

* `f` and `g` are differentiable in the open right half-plane and are continuous on its closure;
* `‖f z‖` and `‖g z‖` are bounded from above by `A * exp(B * (abs z) ^ c)` on the open right
  half-plane for some `c < 2`;
* `‖f z‖` and `‖g z‖` are bounded from above by constants on the imaginary axis;
* `f x - g x`, `x : ℝ`, tends to zero superexponentially fast as `x → ∞`:
  for any natural `n`, `exp (n * x) * ‖f x - g x‖` tends to zero as `x → ∞`.

Then `f` is equal to `g` on the closed right half-plane. -/
theorem eqOn_right_half_plane_of_superexponential_decay {g : ℂ → E}
    (hfd : DiffContOnCl ℂ f {z | 0 < z.re}) (hgd : DiffContOnCl ℂ g {z | 0 < z.re})
    (hfexp : ∃ c < (2 : ℝ), ∃ B,
      f =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hgexp : ∃ c < (2 : ℝ), ∃ B,
      g =O[cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}] fun z => expR (B * abs z ^ c))
    (hre : SuperpolynomialDecay atTop expR fun x => ‖f x - g x‖)
    (hfim : ∃ C, ∀ x : ℝ, ‖f (x * I)‖ ≤ C) (hgim : ∃ C, ∀ x : ℝ, ‖g (x * I)‖ ≤ C) :
    EqOn f g {z : ℂ | 0 ≤ z.re} := by
  suffices EqOn (f - g) 0 {z : ℂ | 0 ≤ z.re} by
    simpa only [EqOn, Pi.sub_apply, Pi.zero_apply, sub_eq_zero] using this
  refine' eq_zero_on_right_half_plane_of_superexponential_decay (hfd.sub hgd) _ hre _
  · set l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z : ℂ | 0 < z.re}
    suffices ∀ {c₁ c₂ B₁ B₂ : ℝ}, c₁ ≤ c₂ → B₁ ≤ B₂ → 0 ≤ B₂ →
        (fun z => expR (B₁ * abs z ^ c₁)) =O[l] fun z => expR (B₂ * abs z ^ c₂) by
      rcases hfexp with ⟨cf, hcf, Bf, hOf⟩; rcases hgexp with ⟨cg, hcg, Bg, hOg⟩
      

Proof state:
case intro.intro.intro.intro.intro.intro
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℂ E
a b C : ℝ
f g✝ : ℂ → E
z : ℂ
g : ℂ → E
hfd : DiffContOnCl ℂ f {z | 0 < z.re}
hgd : DiffContOnCl ℂ g {z | 0 < z.re}
hre : SuperpolynomialDecay atTop expR fun x => ‖f ↑x - g ↑x‖
hfim : ∃ C, ∀ (x : ℝ), ‖f (↑x * I)‖ ≤ C
hgim : ∃ C, ∀ (x : ℝ), ‖g (↑x * I)‖ ≤ C
l : Filter ℂ := cobounded ℂ ⊓ 𝓟 {z | 0 < z.re}
this :
  ∀ {c₁ c₂ B₁ B₂ : ℝ},
    c₁ ≤ c₂ → B₁ ≤ B₂ → 0 ≤ B₂ → (fun z => expR (B₁ * Complex.abs z ^ c₁)) =O[l] fun z => expR (B₂ * Complex.abs z ^ c₂)
cf : ℝ
hcf : cf < 2
Bf : ℝ
hOf : f =O[l] fun z => expR (Bf * Complex.abs z ^ cf)
cg : ℝ
hcg : cg < 2
Bg : ℝ
hOg : g =O[l] fun z => expR (Bg * Complex.abs z ^ cg)
⊢ ∃ c < 2, ∃ B, (f - g) =O[l] fun z => expR (B * Complex.abs z ^ c)

Next tactic:
refine' ⟨max cf cg, max_lt hcf hcg, max 0 (max Bf Bg), _⟩