Theorem: Polynomial.Gal.card_complex_roots_eq_card_real_add_card_not_gal_inv
File: Mathlib/Analysis/Complex/Polynomial.lean

tactic: by_cases hp : p = 0
state_before: p : ℚ[X]
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card
state_after: case pos
p : ℚ[X]
hp : p = 0
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card

case neg
p : ℚ[X]
hp : ¬p = 0
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card

tactic: have inj : Function.Injective (IsScalarTower.toAlgHom ℚ ℝ ℂ) := (algebraMap ℝ ℂ).injective
state_before: case neg
p : ℚ[X]
hp : ¬p = 0
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card
state_after: case neg
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card

tactic: rw [← Finset.card_image_of_injective _ Subtype.coe_injective, ←
  Finset.card_image_of_injective _ inj]
state_before: case neg
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card
state_after: case neg
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

tactic: let a : Finset ℂ := ?_
state_before: case neg
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card
state_after: case neg.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ Finset ℂ

tactic: on_goal 1 => let b : Finset ℂ := ?_
state_before: case neg.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ Finset ℂ
state_after: case neg.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ Finset ℂ

case neg.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ Finset ℂ

tactic: on_goal 1 => let c : Finset ℂ := ?_
state_before: case neg.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ Finset ℂ

case neg.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ Finset ℂ
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
c : Finset ℂ := ?neg.refine_2.refine_2.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_2.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
⊢ Finset ℂ

case neg.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ Finset ℂ

case neg.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ Finset ℂ

tactic: suffices a.card = b.card + c.card by exact this
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
c : Finset ℂ := ?neg.refine_2.refine_2.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_2.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
⊢ Finset ℂ

case neg.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ Finset ℂ

case neg.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
⊢ Finset ℂ
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
⊢ a.card = b.card + c.card

tactic: have ha : ∀ z : ℂ, z ∈ a ↔ aeval z p = 0 := by
  intro z; rw [Set.mem_toFinset, mem_rootSet_of_ne hp]
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
⊢ a.card = b.card + c.card
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
⊢ a.card = b.card + c.card

tactic: have hc0 :
  ∀ w : p.rootSet ℂ, galActionHom p ℂ (restrict p ℂ (Complex.conjAe.restrictScalars ℚ)) w = w ↔
      w.val.im = 0 := by
  intro w
  rw [Subtype.ext_iff, galActionHom_restrict]
  exact Complex.conj_eq_iff_im
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
⊢ a.card = b.card + c.card
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
⊢ a.card = b.card + c.card

tactic: rw [← Finset.card_union_of_disjoint]
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ a.card = b.card + c.card
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ a.card = (b ∪ c).card

case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ Disjoint b c

tactic: haveI : IsEmpty (p.rootSet ℂ) := by rw [hp, rootSet_zero]; infer_instance
state_before: case pos
p : ℚ[X]
hp : p = 0
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card
state_after: case pos
p : ℚ[X]
hp : p = 0
this : IsEmpty ↑(p.rootSet ℂ)
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card

tactic: simp_rw [(galActionHom p ℂ _).support.eq_empty_of_isEmpty, hp, rootSet_zero,
  Set.toFinset_empty, Finset.card_empty]
state_before: case pos
p : ℚ[X]
hp : p = 0
this : IsEmpty ↑(p.rootSet ℂ)
⊢ (p.rootSet ℂ).toFinset.card =
    (p.rootSet ℝ).toFinset.card + ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support.card
state_after: no goals

tactic: rw [hp, rootSet_zero]
state_before: p : ℚ[X]
hp : p = 0
⊢ IsEmpty ↑(p.rootSet ℂ)
state_after: p : ℚ[X]
hp : p = 0
⊢ IsEmpty ↑∅

tactic: infer_instance
state_before: p : ℚ[X]
hp : p = 0
⊢ IsEmpty ↑∅
state_after: no goals

tactic: let b : Finset ℂ := ?_
state_before: case neg.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card
state_after: case neg.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
⊢ Finset ℂ

tactic: let c : Finset ℂ := ?_
state_before: case neg.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
c : Finset ℂ := ?neg.refine_2.refine_2.refine_1✝
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card

case neg.refine_2.refine_2.refine_1
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
⊢ Finset ℂ

tactic: exact this
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := ?neg.refine_1✝
b : Finset ℂ := ?neg.refine_2.refine_1✝
c : Finset ℂ := ?neg.refine_2.refine_2.refine_1✝
this : a.card = b.card + c.card
⊢ (p.rootSet ℂ).toFinset.card =
    (Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset).card +
      (Finset.image (fun a => ↑a)
          ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support).card
state_after: no goals

tactic: intro z
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
⊢ ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
state_after: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
z : ℂ
⊢ z ∈ a ↔ (aeval z) p = 0

tactic: rw [Set.mem_toFinset, mem_rootSet_of_ne hp]
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
z : ℂ
⊢ z ∈ a ↔ (aeval z) p = 0
state_after: no goals

tactic: intro z
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
⊢ ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
state_after: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0

tactic: simp_rw [b, Finset.mem_image, Set.mem_toFinset, mem_rootSet_of_ne hp]
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
state_after: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ (∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z) ↔ (aeval z) p = 0 ∧ z.im = 0

tactic: constructor
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ (∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z) ↔ (aeval z) p = 0 ∧ z.im = 0
state_after: case mp
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ (∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z) → (aeval z) p = 0 ∧ z.im = 0

case mpr
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ (aeval z) p = 0 ∧ z.im = 0 → ∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z

tactic: rintro ⟨w, hw, rfl⟩
state_before: case mp
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ (∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z) → (aeval z) p = 0 ∧ z.im = 0
state_after: case mp.intro.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
w : ℝ
hw : (aeval w) p = 0
⊢ (aeval ((IsScalarTower.toAlgHom ℚ ℝ ℂ) w)) p = 0 ∧ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) w).im = 0

tactic: exact ⟨by rw [aeval_algHom_apply, hw, AlgHom.map_zero], rfl⟩
state_before: case mp.intro.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
w : ℝ
hw : (aeval w) p = 0
⊢ (aeval ((IsScalarTower.toAlgHom ℚ ℝ ℂ) w)) p = 0 ∧ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) w).im = 0
state_after: no goals

tactic: rw [aeval_algHom_apply, hw, AlgHom.map_zero]
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
w : ℝ
hw : (aeval w) p = 0
⊢ (aeval ((IsScalarTower.toAlgHom ℚ ℝ ℂ) w)) p = 0
state_after: no goals

tactic: rintro ⟨hz1, hz2⟩
state_before: case mpr
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
⊢ (aeval z) p = 0 ∧ z.im = 0 → ∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z
state_after: case mpr.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ ∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z

tactic: exact ⟨z.re, inj (by rwa [← aeval_algHom_apply, key, AlgHom.map_zero]), key⟩
state_before: case mpr.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
key : (IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re = z
⊢ ∃ a, (aeval a) p = 0 ∧ (IsScalarTower.toAlgHom ℚ ℝ ℂ) a = z
state_after: no goals

tactic: ext
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ (IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re = z
state_after: case a
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re).re = z.re

case a
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re).im = z.im

tactic: rfl
state_before: case a
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re).re = z.re
state_after: no goals

tactic: rw [hz2]
state_before: case a
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re).im = z.im
state_after: case a
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re).im = 0

tactic: rfl
state_before: case a
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
⊢ ((IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re).im = 0
state_after: no goals

tactic: rwa [← aeval_algHom_apply, key, AlgHom.map_zero]
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im = 0
key : (IsScalarTower.toAlgHom ℚ ℝ ℂ) z.re = z
⊢ (IsScalarTower.toAlgHom ℚ ℝ ℂ) ((aeval z.re) p) = (IsScalarTower.toAlgHom ℚ ℝ ℂ) 0
state_after: no goals

tactic: intro w
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
⊢ ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
state_after: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
w : ↑(p.rootSet ℂ)
⊢ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0

tactic: rw [Subtype.ext_iff, galActionHom_restrict]
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
w : ↑(p.rootSet ℂ)
⊢ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
state_after: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
w : ↑(p.rootSet ℂ)
⊢ (AlgEquiv.restrictScalars ℚ conjAe) ↑w = ↑w ↔ (↑w).im = 0

tactic: exact Complex.conj_eq_iff_im
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
w : ↑(p.rootSet ℂ)
⊢ (AlgEquiv.restrictScalars ℚ conjAe) ↑w = ↑w ↔ (↑w).im = 0
state_after: no goals

tactic: intro z
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
⊢ ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
state_after: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0

tactic: simp_rw [c, Finset.mem_image]
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
state_after: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ (∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z) ↔
    (aeval z) p = 0 ∧ z.im ≠ 0

tactic: constructor
state_before: p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ (∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z) ↔
    (aeval z) p = 0 ∧ z.im ≠ 0
state_after: case mp
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ (∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z) →
    (aeval z) p = 0 ∧ z.im ≠ 0

case mpr
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ (aeval z) p = 0 ∧ z.im ≠ 0 →
    ∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z

tactic: rintro ⟨w, hw, rfl⟩
state_before: case mp
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ (∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z) →
    (aeval z) p = 0 ∧ z.im ≠ 0
state_after: case mp.intro.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
w : { x // x ∈ p.rootSet ℂ }
hw : w ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
⊢ (aeval ↑w) p = 0 ∧ (↑w).im ≠ 0

tactic: exact ⟨(mem_rootSet.mp w.2).2, mt (hc0 w).mpr (Equiv.Perm.mem_support.mp hw)⟩
state_before: case mp.intro.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
w : { x // x ∈ p.rootSet ℂ }
hw : w ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
⊢ (aeval ↑w) p = 0 ∧ (↑w).im ≠ 0
state_after: no goals

tactic: rintro ⟨hz1, hz2⟩
state_before: case mpr
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
⊢ (aeval z) p = 0 ∧ z.im ≠ 0 →
    ∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z
state_after: case mpr.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im ≠ 0
⊢ ∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z

tactic: exact ⟨⟨z, mem_rootSet.mpr ⟨hp, hz1⟩⟩, Equiv.Perm.mem_support.mpr (mt (hc0 _).mp hz2), rfl⟩
state_before: case mpr.intro
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
z : ℂ
hz1 : (aeval z) p = 0
hz2 : z.im ≠ 0
⊢ ∃ a ∈ ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support, ↑a = z
state_after: no goals

tactic: apply congr_arg Finset.card
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ a.card = (b ∪ c).card
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ a = b ∪ c

tactic: simp_rw [Finset.ext_iff, Finset.mem_union, ha, hb, hc]
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ a = b ∪ c
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ ∀ (a : ℂ), (aeval a) p = 0 ↔ (aeval a) p = 0 ∧ a.im = 0 ∨ (aeval a) p = 0 ∧ a.im ≠ 0

tactic: tauto
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ ∀ (a : ℂ), (aeval a) p = 0 ↔ (aeval a) p = 0 ∧ a.im = 0 ∨ (aeval a) p = 0 ∧ a.im ≠ 0
state_after: no goals

tactic: rw [Finset.disjoint_left]
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ Disjoint b c
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ ∀ ⦃a : ℂ⦄, a ∈ b → a ∉ c

tactic: intro z
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
⊢ ∀ ⦃a : ℂ⦄, a ∈ b → a ∉ c
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
z : ℂ
⊢ z ∈ b → z ∉ c

tactic: rw [hb, hc]
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
z : ℂ
⊢ z ∈ b → z ∉ c
state_after: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
z : ℂ
⊢ (aeval z) p = 0 ∧ z.im = 0 → ¬((aeval z) p = 0 ∧ z.im ≠ 0)

tactic: tauto
state_before: case neg.refine_2.refine_2.refine_2
p : ℚ[X]
hp : ¬p = 0
inj : Function.Injective ⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)
a : Finset ℂ := (p.rootSet ℂ).toFinset
b : Finset ℂ := Finset.image (⇑(IsScalarTower.toAlgHom ℚ ℝ ℂ)) (p.rootSet ℝ).toFinset
c : Finset ℂ :=
  Finset.image (fun a => ↑a) ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))).support
ha : ∀ (z : ℂ), z ∈ a ↔ (aeval z) p = 0
hb : ∀ (z : ℂ), z ∈ b ↔ (aeval z) p = 0 ∧ z.im = 0
hc0 :
  ∀ (w : ↑(p.rootSet ℂ)), ((galActionHom p ℂ) ((restrict p ℂ) (AlgEquiv.restrictScalars ℚ conjAe))) w = w ↔ (↑w).im = 0
hc : ∀ (z : ℂ), z ∈ c ↔ (aeval z) p = 0 ∧ z.im ≠ 0
z : ℂ
⊢ (aeval z) p = 0 ∧ z.im = 0 → ¬((aeval z) p = 0 ∧ z.im ≠ 0)
state_after: no goals