Theorem: MeromorphicAt.order_eq_int_iff
File: Mathlib/Analysis/Analytic/Meromorphic.lean

tactic: unfold order
state_before: 𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
⊢ hf.order = ↑n ↔ ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: 𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: by_cases h : hf.choose_spec.order = ⊤
state_before: 𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ⋯.order = ⊤
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

case neg
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ¬⋯.order = ⊤
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: rw [h, WithTop.map_top, ← WithTop.coe_natCast, top_sub,
  eq_false_intro WithTop.top_ne_coe, false_iff]
state_before: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ⋯.order = ⊤
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ⋯.order = ⊤
⊢ ¬∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: rw [AnalyticAt.order_eq_top_iff] at h
state_before: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ⋯.order = ⊤
⊢ ¬∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
⊢ ¬∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: refine fun ⟨g, hg_an, hg_ne, hg_eq⟩ ↦ hg_ne ?_
state_before: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
⊢ ¬∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ g x = 0

tactic: apply EventuallyEq.eq_of_nhds
state_before: case pos
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ g x = 0
state_after: case pos.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ g =ᶠ[𝓝 x] fun {x} => 0

tactic: rw [EventuallyEq, ← AnalyticAt.frequently_eq_iff_eventually_eq hg_an analyticAt_const]
state_before: case pos.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ g =ᶠ[𝓝 x] fun {x} => 0
state_after: case pos.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ ∃ᶠ (z : 𝕜) in 𝓝[≠] x, g z = 0

tactic: apply Eventually.frequently
state_before: case pos.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ ∃ᶠ (z : 𝕜) in 𝓝[≠] x, g z = 0
state_after: case pos.h.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ ∀ᶠ (x : 𝕜) in 𝓝[≠] x, g x = 0

tactic: rw [eventually_nhdsWithin_iff] at hg_eq ⊢
state_before: case pos.h.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
⊢ ∀ᶠ (x : 𝕜) in 𝓝[≠] x, g x = 0
state_after: case pos.h.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ n • g x_1
⊢ ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → g x_1 = 0

tactic: filter_upwards [h, hg_eq] with z hfz hfz_eq hz
state_before: case pos.h.h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ n • g x_1
⊢ ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → g x_1 = 0
state_after: case h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ n • g x_1
z : 𝕜
hfz : (z - x) ^ Exists.choose hf • f z = 0
hfz_eq : z ∈ {x}ᶜ → f z = (z - x) ^ n • g z
hz : z ∈ {x}ᶜ
⊢ g z = 0

tactic: rwa [hfz_eq hz, ← mul_smul, smul_eq_zero_iff_right] at hfz
state_before: case h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ n • g x_1
z : 𝕜
hfz : (z - x) ^ Exists.choose hf • f z = 0
hfz_eq : z ∈ {x}ᶜ → f z = (z - x) ^ n • g z
hz : z ∈ {x}ᶜ
⊢ g z = 0
state_after: case h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ n • g x_1
z : 𝕜
hfz : ((z - x) ^ Exists.choose hf * (z - x) ^ n) • g z = 0
hfz_eq : z ∈ {x}ᶜ → f z = (z - x) ^ n • g z
hz : z ∈ {x}ᶜ
⊢ (z - x) ^ Exists.choose hf * (z - x) ^ n ≠ 0

tactic: exact mul_ne_zero (pow_ne_zero _ (sub_ne_zero.mpr hz)) (zpow_ne_zero _ (sub_ne_zero.mpr hz))
state_before: case h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = 0
x✝ : ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ n • g x_1
z : 𝕜
hfz : ((z - x) ^ Exists.choose hf * (z - x) ^ n) • g z = 0
hfz_eq : z ∈ {x}ᶜ → f z = (z - x) ^ n • g z
hz : z ∈ {x}ᶜ
⊢ (z - x) ^ Exists.choose hf * (z - x) ^ n ≠ 0
state_after: no goals

tactic: obtain ⟨m, h⟩ := WithTop.ne_top_iff_exists.mp h
state_before: case neg
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h : ¬⋯.order = ⊤
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case neg.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: rw [← h, WithTop.map_coe, ← WithTop.coe_natCast, ← coe_sub, WithTop.coe_inj]
state_before: case neg.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
⊢ WithTop.map (fun x => ↑x) ⋯.order - ↑(Exists.choose hf) = ↑n ↔
    ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case neg.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
⊢ ↑m - ↑(Exists.choose hf) = n ↔ ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: obtain ⟨g, hg_an, hg_ne, hg_eq⟩ := (AnalyticAt.order_eq_nat_iff _ _).mp h.symm
state_before: case neg.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
⊢ ↑m - ↑(Exists.choose hf) = n ↔ ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case neg.intro.intro.intro.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
⊢ ↑m - ↑(Exists.choose hf) = n ↔ ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: replace hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ (↑m - ↑hf.choose : ℤ) • g z := by
  rw [eventually_nhdsWithin_iff]
  filter_upwards [hg_eq] with z hg_eq hz
  rwa [← smul_right_inj <| zpow_ne_zero _ (sub_ne_zero.mpr hz), ← mul_smul,
    ← zpow_add₀ (sub_ne_zero.mpr hz), ← add_sub_assoc, add_sub_cancel_left, zpow_natCast,
    zpow_natCast]
state_before: case neg.intro.intro.intro.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
⊢ ↑m - ↑(Exists.choose hf) = n ↔ ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: case neg.intro.intro.intro.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ (↑m - ↑(Exists.choose hf)) • g z
⊢ ↑m - ↑(Exists.choose hf) = n ↔ ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z

tactic: exact ⟨fun h ↦ ⟨g, hg_an, hg_ne, h ▸ hg_eq⟩,
  AnalyticAt.unique_eventuallyEq_zpow_smul_nonzero ⟨g, hg_an, hg_ne, hg_eq⟩⟩
state_before: case neg.intro.intro.intro.intro
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ (↑m - ↑(Exists.choose hf)) • g z
⊢ ↑m - ↑(Exists.choose hf) = n ↔ ∃ g, AnalyticAt 𝕜 g x ∧ g x ≠ 0 ∧ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ n • g z
state_after: no goals

tactic: rw [eventually_nhdsWithin_iff]
state_before: 𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
⊢ ∀ᶠ (z : 𝕜) in 𝓝[≠] x, f z = (z - x) ^ (↑m - ↑(Exists.choose hf)) • g z
state_after: 𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
⊢ ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ (↑m - ↑(Exists.choose hf)) • g x_1

tactic: filter_upwards [hg_eq] with z hg_eq hz
state_before: 𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
⊢ ∀ᶠ (x_1 : 𝕜) in 𝓝 x, x_1 ∈ {x}ᶜ → f x_1 = (x_1 - x) ^ (↑m - ↑(Exists.choose hf)) • g x_1
state_after: case h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq✝ : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
z : 𝕜
hg_eq : (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
hz : z ∈ {x}ᶜ
⊢ f z = (z - x) ^ (↑m - ↑(Exists.choose hf)) • g z

tactic: rwa [← smul_right_inj <| zpow_ne_zero _ (sub_ne_zero.mpr hz), ← mul_smul,
  ← zpow_add₀ (sub_ne_zero.mpr hz), ← add_sub_assoc, add_sub_cancel_left, zpow_natCast,
  zpow_natCast]
state_before: case h
𝕜 : Type u_1
inst✝² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
x : 𝕜
hf : MeromorphicAt f x
n : ℤ
h✝ : ¬⋯.order = ⊤
m : ℕ
h : ↑m = ⋯.order
g : 𝕜 → E
hg_an : AnalyticAt 𝕜 g x
hg_ne : g x ≠ 0
hg_eq✝ : ∀ᶠ (z : 𝕜) in 𝓝 x, (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
z : 𝕜
hg_eq : (z - x) ^ Exists.choose hf • f z = (z - x) ^ m • g z
hz : z ∈ {x}ᶜ
⊢ f z = (z - x) ^ (↑m - ↑(Exists.choose hf)) • g z
state_after: no goals