Module: Mathlib.NumberTheory.NumberField.CanonicalEmbedding.ConvexBody

Goal state before:
pp: case refine_1
K : Type u_1
inst✝ : Field K
f : InfinitePlace K → ℝ≥0
w₀ : { w // w.IsComplex }
x : K
x✝ :
  (∀ (a : InfinitePlace K), a.IsReal → a x < ↑(f a)) ∧
    ∀ (a : InfinitePlace K) (b : a.IsComplex),
      a.embedding x ∈ if ⟨a, b⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f a) ^ 2} else ball 0 ↑(f a)
h₁ : ∀ (a : InfinitePlace K), a.IsReal → a x < ↑(f a)
h₂ :
  ∀ (a : InfinitePlace K) (b : a.IsComplex),
    a.embedding x ∈ if ⟨a, b⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f a) ^ 2} else ball 0 ↑(f a)
w : InfinitePlace K
h_ne : w ≠ ↑w₀
⊢ w x < ↑(f w)

pp: case refine_2
K : Type u_1
inst✝ : Field K
f : InfinitePlace K → ℝ≥0
w₀ : { w // w.IsComplex }
x : K
x✝ :
  (∀ (a : InfinitePlace K), a.IsReal → a x < ↑(f a)) ∧
    ∀ (a : InfinitePlace K) (b : a.IsComplex),
      a.embedding x ∈ if ⟨a, b⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f a) ^ 2} else ball 0 ↑(f a)
h₁ : ∀ (a : InfinitePlace K), a.IsReal → a x < ↑(f a)
h₂ :
  ∀ (a : InfinitePlace K) (b : a.IsComplex),
    a.embedding x ∈ if ⟨a, b⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f a) ^ 2} else ball 0 ↑(f a)
⊢ |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2

pp: case refine_3
K : Type u_1
inst✝ : Field K
f : InfinitePlace K → ℝ≥0
w₀ : { w // w.IsComplex }
x : K
x✝ :
  (∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)) ∧
    |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
h₁ : ∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)
h₂ : |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
w : InfinitePlace K
hw : w.IsReal
⊢ w x < ↑(f w)

pp: case refine_4
K : Type u_1
inst✝ : Field K
f : InfinitePlace K → ℝ≥0
w₀ : { w // w.IsComplex }
x : K
x✝ :
  (∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)) ∧
    |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
h₁ : ∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)
h₂ : |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
w : InfinitePlace K
hw : w.IsComplex
⊢ w.embedding x ∈ if ⟨w, hw⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f w) ^ 2} else ball 0 ↑(f w)

Tactic:
· by_cases hw : IsReal w
    · exact norm_embedding_eq w _ ▸ h₁ w hw
    · specialize h₂ w (not_isReal_iff_isComplex.mp hw)
      rw [apply_ite (w.embedding x ∈ ·), Set.mem_ofPred_eq,
        mem_ball_zero_iff, norm_embedding_eq] at h₂
      rwa [if_neg (by exact Subtype.coe_ne_coe.1 h_ne)] at h₂

Goal state after:
case refine_2
K : Type u_1
inst✝ : Field K
f : InfinitePlace K → ℝ≥0
w₀ : { w // w.IsComplex }
x : K
x✝ :
  (∀ (a : InfinitePlace K), a.IsReal → a x < ↑(f a)) ∧
    ∀ (a : InfinitePlace K) (b : a.IsComplex),
      a.embedding x ∈ if ⟨a, b⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f a) ^ 2} else ball 0 ↑(f a)
h₁ : ∀ (a : InfinitePlace K), a.IsReal → a x < ↑(f a)
h₂ :
  ∀ (a : InfinitePlace K) (b : a.IsComplex),
    a.embedding x ∈ if ⟨a, b⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f a) ^ 2} else ball 0 ↑(f a)
⊢ |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2

case refine_3
K : Type u_1
inst✝ : Field K
f : InfinitePlace K → ℝ≥0
w₀ : { w // w.IsComplex }
x : K
x✝ :
  (∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)) ∧
    |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
h₁ : ∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)
h₂ : |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
w : InfinitePlace K
hw : w.IsReal
⊢ w x < ↑(f w)

case refine_4
K : Type u_1
inst✝ : Field K
f : InfinitePlace K → ℝ≥0
w₀ : { w // w.IsComplex }
x : K
x✝ :
  (∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)) ∧
    |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
h₁ : ∀ (w : InfinitePlace K), w ≠ ↑w₀ → w x < ↑(f w)
h₂ : |((↑w₀).embedding x).re| < 1 ∧ |((↑w₀).embedding x).im| < ↑(f ↑w₀) ^ 2
w : InfinitePlace K
hw : w.IsComplex
⊢ w.embedding x ∈ if ⟨w, hw⟩ = w₀ then {x | |x.re| < 1 ∧ |x.im| < ↑(f w) ^ 2} else ball 0 ↑(f w)