-- Mathlib/Analysis/Analytic/CPolynomial.lean
theorem hasFiniteFPowerSeriesOnBall_uncurry_of_multilinear :
    HasFiniteFPowerSeriesOnBall (fun (p : G × (Π i, Em i)) ↦ f p.1 p.2)
      f.toFormalMultilinearSeriesOfMultilinear 0 (Fintype.card (Option ι) + 1) ⊤

Proof state:
𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
⊢ ∀ (m : ℕ), Fintype.card (Option ι) + 1 ≤ m → f.toFormalMultilinearSeriesOfMultilinear m = 0

Tactic:
intro m hm

Result:
𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
m : ℕ
hm : Fintype.card (Option ι) + 1 ≤ m
⊢ f.toFormalMultilinearSeriesOfMultilinear m = 0

Proof state:
𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
⊢ HasFiniteFPowerSeriesOnBall (fun p => (f p.1) p.2) f.toFormalMultilinearSeriesOfMultilinear 0
    (Fintype.card (Option ι) + 1) ⊤

Tactic:
apply HasFiniteFPowerSeriesOnBall.mk' ?_ ENNReal.zero_lt_top  ?_

Result:
𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
⊢ ∀ (m : ℕ), Fintype.card (Option ι) + 1 ≤ m → f.toFormalMultilinearSeriesOfMultilinear m = 0

𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
⊢ ∀ y ∈ EMetric.ball 0 ⊤,
    (∑ i ∈ Finset.range (Fintype.card (Option ι) + 1), (f.toFormalMultilinearSeriesOfMultilinear i) fun x => y) =
      (f (0 + y).1) (0 + y).2

Proof state:
𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
y : G × ((i : ι) → Em i)
a✝ : y ∈ EMetric.ball 0 ⊤
⊢ ((ContinuousMultilinearMap.domDomCongr (Fintype.equivFinOfCardEq ⋯) f.continuousMultilinearMapOption) fun x => y) =
    (f y.1) y.2

Tactic:
rfl

Result:
no goals

Proof state:
𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
y : G × ((i : ι) → Em i)
a✝ : y ∈ EMetric.ball 0 ⊤
⊢ ((f.toFormalMultilinearSeriesOfMultilinear (Fintype.card (Option ι))) fun x => y) = (f y.1) y.2

Tactic:
rw [toFormalMultilinearSeriesOfMultilinear, dif_pos rfl]

Result:
𝕜 : Type u_1
F : Type u_3
G : Type u_4
inst✝⁷ : NontriviallyNormedField 𝕜
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace 𝕜 F
inst✝⁴ : NormedAddCommGroup G
inst✝³ : NormedSpace 𝕜 G
ι : Type u_5
Em : ι → Type u_6
inst✝² : (i : ι) → NormedAddCommGroup (Em i)
inst✝¹ : (i : ι) → NormedSpace 𝕜 (Em i)
inst✝ : Fintype ι
f : G →L[𝕜] ContinuousMultilinearMap 𝕜 Em F
y : G × ((i : ι) → Em i)
a✝ : y ∈ EMetric.ball 0 ⊤
⊢ ((ContinuousMultilinearMap.domDomCongr (Fintype.equivFinOfCardEq ⋯) f.continuousMultilinearMapOption) fun x => y) =
    (f y.1) y.2