mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.ModelTheory.Substructures

Goal state before:
pp: L : Language
M : Type w
N : Type u_1
P : Type u_2
inst✝² : L.Structure M
inst✝¹ : L.Structure N
inst✝ : L.Structure P
S : L.Substructure M
p : L.Substructure N
f✝ : M →[L] N
h : ∀ (c : M), f✝ c ∈ p
n : ℕ
f : L.Functions n
x : Fin n → M
⊢ ⟨f✝ (funMap f x), ⋯⟩ = funMap f ((fun c ↦ ⟨f✝ c, ⋯⟩) ∘ x)

Tactic:
by aesop

Goal state after:
Module: Mathlib.ModelTheory.Encoding

Goal state before:
pp: case rel.refine_2
L : Language
α : Type u'
l✝ : List ((n : ℕ) × L.BoundedFormula α n)
n φ_n φ_l : ℕ
φ_R : L.Relations φ_l
ts : Fin φ_l → L.Term (α ⊕ Fin φ_n)
l : List ((k : ℕ) × L.Term (α ⊕ Fin k) ⊕ (n : ℕ) × L.Relations n ⊕ ℕ)
h :
  ∀ (i : Fin φ_l),
    (List.map Sum.getLeft? (List.map (fun i ↦ Sum.inl ⟨⟨φ_n, rel φ_R ts⟩.fst, ts i⟩) (finRange φ_l) ++ l))[i]?.join =
      some ⟨φ_n, ts i⟩
⊢ listDecode (drop φ_l (List.map (fun i ↦ Sum.inl ⟨φ_n, ts i⟩) (finRange φ_l) ++ l)) = listDecode l

Tactic:
List.drop_append,

Goal state after:
case rel.refine_2
L : Language
α : Type u'
l✝ : List ((n : ℕ) × L.BoundedFormula α n)
n φ_n φ_l : ℕ
φ_R : L.Relations φ_l
ts : Fin φ_l → L.Term (α ⊕ Fin φ_n)
l : List ((k : ℕ) × L.Term (α ⊕ Fin k) ⊕ (n : ℕ) × L.Relations n ⊕ ℕ)
h :
  ∀ (i : Fin φ_l),
    (List.map Sum.getLeft? (List.map (fun i ↦ Sum.inl ⟨⟨φ_n, rel φ_R ts⟩.fst, ts i⟩) (finRange φ_l) ++ l))[i]?.join =
      some ⟨φ_n, ts i⟩
⊢ listDecode
      (drop φ_l (List.map (fun i ↦ Sum.inl ⟨φ_n, ts i⟩) (finRange φ_l)) ++
        drop (φ_l - (List.map (fun i ↦ Sum.inl ⟨φ_n, ts i⟩) (finRange φ_l)).length) l) =
    listDecode l
Module: Mathlib.ModelTheory.Semantics

Goal state before:
pp: L : Language
M : Type w
inst✝¹ : L.Structure M
α : Type u'
γ : Type u_3
inst✝ : Finite γ
φ : L.Formula (α ⊕ γ)
v : α → M
v' : Fin 0 → M
⊢ Realize (Formula.iExsUnique γ φ) v v' ↔ ∃! i, φ.Realize (Sum.elim v i)

Tactic:
by
  rw [← Formula.realize_iExsUnique, iff_iff_eq]; congr; simp [eq_iff_true_of_subsingleton]

Goal state after:
Module: Mathlib.GroupTheory.OreLocalization.Cardinality

Goal state before:
pp: case inr
R : Type u
inst✝² : Monoid R
S : Submonoid R
inst✝¹ : OreSet S
X : Type v
inst✝ : MulAction R X
hc : ∀ (s s' : ↥S), Commute s s'
h✝ : Infinite X
⊢ #(OreLocalization S X) ≤ lift.{u, v} #X

Tactic:
have key (x : X) (s s' : S) (h : s • x = s' • x) (hc : Commute s s') : x /ₒ s = x /ₒ s' := by
    rw [oreDiv_eq_iff]
    refine ⟨s, s'.1, h, ?_⟩
    · exact_mod_cast hc

Goal state after:
case inr
R : Type u
inst✝² : Monoid R
S : Submonoid R
inst✝¹ : OreSet S
X : Type v
inst✝ : MulAction R X
hc : ∀ (s s' : ↥S), Commute s s'
h✝ : Infinite X
key : ∀ (x : X) (s s' : ↥S), s • x = s' • x → Commute s s' → x /ₒ s = x /ₒ s'
⊢ #(OreLocalization S X) ≤ lift.{u, v} #X
Module: Mathlib.SetTheory.Cardinal.Divisibility

Goal state before:
pp: case refine_1
a : Cardinal.{u}
ha : ℵ₀ ≤ a
⊢ ¬IsUnit a

pp: case refine_2
a : Cardinal.{u}
ha : ℵ₀ ≤ a
b c : Cardinal.{u}
hbc : a ∣ b * c
⊢ a ∣ b ∨ a ∣ c

Tactic:
· rw [isUnit_iff]
    exact (one_lt_aleph0.trans_le ha).ne'

Goal state after:
case refine_2
a : Cardinal.{u}
ha : ℵ₀ ≤ a
b c : Cardinal.{u}
hbc : a ∣ b * c
⊢ a ∣ b ∨ a ∣ c
Module: Mathlib.SetTheory.Cardinal.Divisibility

Goal state before:
pp: a✝ a : Cardinal.{u}
ha : ℵ₀ ≤ a
b c : Cardinal.{u}
hbc : a ∣ b * c
hz : b * c ≠ 0
h : c ≤ b
habc : a ≤ b * c
⊢ a ∣ b

Tactic:
rwa [mul_eq_max' <| ha.trans <| habc, max_def', if_pos h] at hbc

Goal state after:
Module: Mathlib.FieldTheory.FinTrdeg

Goal state before:
pp: K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : FinTrdeg K L
ι : Type u_3
x : ι → L
hx : IsTranscendenceBasis K x
⊢ Finite ι

Tactic:
← Cardinal.mk_lt_aleph0_iff,

Goal state after:
K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : FinTrdeg K L
ι : Type u_3
x : ι → L
hx : IsTranscendenceBasis K x
⊢ Cardinal.mk ι < Cardinal.aleph0
Module: Mathlib.FieldTheory.FinTrdeg

Goal state before:
pp: K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : FinTrdeg K L
ι : Type u_3
x : ι → L
hx : AlgebraicIndependent K x
⊢ Finite ι

Tactic:
← Cardinal.mk_lt_aleph0_iff,

Goal state after:
K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : FinTrdeg K L
ι : Type u_3
x : ι → L
hx : AlgebraicIndependent K x
⊢ Cardinal.mk ι < Cardinal.aleph0
Module: Mathlib.FieldTheory.Finite.Extension

Goal state before:
pp: k : Type u_1
inst✝¹ : Field k
inst✝ : Finite k
f : k[X]
hi : Irreducible f
n : ℕ
hdvd : f.natDegree ∣ n
a : AdjoinRoot f := AdjoinRoot.root f
this✝ : NeZero f.natDegree
this : Fact (Irreducible f)
⊢ (aeval a) f = 0

Tactic:
by aesop

Goal state after:
Module: Mathlib.FieldTheory.IntermediateField.ExtendRight

Goal state before:
pp: K : Type u_1
L : Type u_2
inst✝¹⁰ : Field K
inst✝⁹ : Field L
inst✝⁸ : Algebra K L
F : IntermediateField K L
M : Type u_3
inst✝⁷ : Field M
inst✝⁶ : Algebra K M
inst✝⁵ : Algebra L M
inst✝⁴ : IsScalarTower K L M
S : Type u_5
inst✝³ : CommRing S
inst✝² : Algebra S ↥F
inst✝¹ : Algebra S M
inst✝ : IsScalarTower S (↥F) M
s : S
⊢ (algebraMap S M) s ∈ F.extendRight M

Tactic:
by
  rw [IsScalarTower.algebraMap_apply S F M, IsScalarTower.algebraMap_apply F L M]
  exact ⟨algebraMap F L (algebraMap S F s), by simp, rfl⟩

Goal state after:
Module: Mathlib.FieldTheory.CardinalEmb

Goal state before:
pp: case neg
F : Type u
E : Type v
inst✝³ : Field F
inst✝² : Field E
inst✝¹ : Algebra F E
inst✝ : Algebra.IsSeparable F E
h : IsNoetherian F E
⊢ finSepDegree F E = finrank F E

Tactic:
finSepDegree_eq_finrank_of_isSeparable

Goal state after:
case neg
F : Type u
E : Type v
inst✝³ : Field F
inst✝² : Field E
inst✝¹ : Algebra F E
inst✝ : Algebra.IsSeparable F E
h : IsNoetherian F E
⊢ finrank F E = finrank F E
Module: Mathlib.FieldTheory.PerfectClosure

Goal state before:
pp: K : Type u
inst✝² : CommRing K
p : ℕ
inst✝¹ : Fact (Nat.Prime p)
inst✝ : CharP K p
n : ℕ
⊢ mk K p (n, 0) = 0

Tactic:
induction n with
  | zero => rfl
  | succ n ih =>
    rw [← ih]
    apply (Quot.sound _).symm
    have := R.intro (p := p) n (0 : K)
    rwa [map_zero] at this

Goal state after:
Module: Mathlib.FieldTheory.IsPerfectClosure

Goal state before:
pp: K : Type u_1
L : Type u_2
M : Type u_3
N : Type u_4
inst✝⁸ : CommRing K
inst✝⁷ : CommRing L
inst✝⁶ : CommRing M
inst✝⁵ : CommRing N
i : K →+* L
j : K →+* M
k : K →+* N
f : L →+* M
g : L →+* N
p : ℕ
inst✝⁴ : ExpChar M p
inst✝³ : ExpChar K p
inst✝² : PerfectRing M p
inst✝¹ : IsPRadical i p
inst✝ : ExpChar L p
x1 x2 : L
n1 : ℕ
y1 : K
h1 : i y1 = x1 ^ p ^ n1
n2 : ℕ
y2 : K
h2 : i y2 = x2 ^ p ^ n2
⊢ (iterateFrobeniusEquiv M p n1).symm (j y1) *
      (iterateFrobeniusEquiv M p n2).symm ((iterateFrobeniusEquiv M p n1).symm (j y2 ^ p ^ n1)) =
    (iterateFrobeniusEquiv M p n1).symm (j y1) * (iterateFrobeniusEquiv M p n2).symm (j y2)

Tactic:
← iterateFrobeniusEquiv_def,

Goal state after:
K : Type u_1
L : Type u_2
M : Type u_3
N : Type u_4
inst✝⁸ : CommRing K
inst✝⁷ : CommRing L
inst✝⁶ : CommRing M
inst✝⁵ : CommRing N
i : K →+* L
j : K →+* M
k : K →+* N
f : L →+* M
g : L →+* N
p : ℕ
inst✝⁴ : ExpChar M p
inst✝³ : ExpChar K p
inst✝² : PerfectRing M p
inst✝¹ : IsPRadical i p
inst✝ : ExpChar L p
x1 x2 : L
n1 : ℕ
y1 : K
h1 : i y1 = x1 ^ p ^ n1
n2 : ℕ
y2 : K
h2 : i y2 = x2 ^ p ^ n2
⊢ (iterateFrobeniusEquiv M p n1).symm (j y1) *
      (iterateFrobeniusEquiv M p n2).symm
        ((iterateFrobeniusEquiv M p n1).symm ((iterateFrobeniusEquiv M p n1) (j y2))) =
    (iterateFrobeniusEquiv M p n1).symm (j y1) * (iterateFrobeniusEquiv M p n2).symm (j y2)
Module: Mathlib.FieldTheory.IsRealClosed.Basic

Goal state before:
pp: R : Type u
inst✝¹ : Field R
inst✝ : IsRealClosed R
x : R
hx : ¬IsSquare (-x)
⊢ IsSquare x

Tactic:
by aesop

Goal state after:
Module: Mathlib.FieldTheory.IsRealClosed.Basic

Goal state before:
pp: R : Type u
inst✝¹ : Field R
inst✝ : IsRealClosed R
x : R
hx : ¬IsSquare x
⊢ IsSquare (-x)

Tactic:
by aesop

Goal state after:
Module: Mathlib.FieldTheory.PerfectClosure

Goal state before:
pp: K : Type u
inst✝² : CommRing K
p : ℕ
inst✝¹ : Fact (Nat.Prime p)
inst✝ : CharP K p
x : ℕ
⊢ ↑x = ↑0 ↔ ↑x = 0

Tactic:
natCast_eq_iff,

Goal state after:
K : Type u
inst✝² : CommRing K
p : ℕ
inst✝¹ : Fact (Nat.Prime p)
inst✝ : CharP K p
x : ℕ
⊢ ↑x = ↑0 ↔ ↑x = 0
Module: Mathlib.FieldTheory.IsPerfectClosure

Goal state before:
pp: K : Type u_1
L : Type u_2
M : Type u_3
N : Type u_4
inst✝⁸ : CommRing K
inst✝⁷ : CommRing L
inst✝⁶ : CommRing M
inst✝⁵ : CommRing N
i : K →+* L
j : K →+* M
k : K →+* N
f : L →+* M
g : L →+* N
p : ℕ
inst✝⁴ : ExpChar M p
inst✝³ : ExpChar K p
inst✝² : PerfectRing M p
inst✝¹ : IsPRadical i p
inst✝ : ExpChar L p
x1 x2 : L
n1 : ℕ
y1 : K
h1 : i y1 = x1 ^ p ^ n1
n2 : ℕ
y2 : K
h2 : i y2 = x2 ^ p ^ n2
⊢ (iterateFrobeniusEquiv M p n1).symm (j y1) +
      (iterateFrobeniusEquiv M p n2).symm ((iterateFrobeniusEquiv M p n1).symm (j y2 ^ p ^ n1)) =
    (iterateFrobeniusEquiv M p n1).symm (j y1) + (iterateFrobeniusEquiv M p n2).symm (j y2)

Tactic:
← iterateFrobeniusEquiv_def,

Goal state after:
K : Type u_1
L : Type u_2
M : Type u_3
N : Type u_4
inst✝⁸ : CommRing K
inst✝⁷ : CommRing L
inst✝⁶ : CommRing M
inst✝⁵ : CommRing N
i : K →+* L
j : K →+* M
k : K →+* N
f : L →+* M
g : L →+* N
p : ℕ
inst✝⁴ : ExpChar M p
inst✝³ : ExpChar K p
inst✝² : PerfectRing M p
inst✝¹ : IsPRadical i p
inst✝ : ExpChar L p
x1 x2 : L
n1 : ℕ
y1 : K
h1 : i y1 = x1 ^ p ^ n1
n2 : ℕ
y2 : K
h2 : i y2 = x2 ^ p ^ n2
⊢ (iterateFrobeniusEquiv M p n1).symm (j y1) +
      (iterateFrobeniusEquiv M p n2).symm
        ((iterateFrobeniusEquiv M p n1).symm ((iterateFrobeniusEquiv M p n1) (j y2))) =
    (iterateFrobeniusEquiv M p n1).symm (j y1) + (iterateFrobeniusEquiv M p n2).symm (j y2)
Module: Mathlib.FieldTheory.IsRealClosed.Basic

Goal state before:
pp: R : Type u
inst✝³ : Field R
inst✝² : IsRealClosed R
inst✝¹ : LinearOrder R
inst✝ : IsStrictOrderedRing R
x : R
h : 0 ≤ x
this : IsSquare (-x) → x = 0
⊢ IsSquare x

Tactic:
by aesop

Goal state after:
Module: Mathlib.RingTheory.Algebraic.LinearIndependent

Goal state before:
pp: F : Type u_1
E : Type u_2
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
x : E
H : ∀ (p : F[X]), (aeval x) p = 0 → p = 0
s : Finset F
m : F → F
i : F
hi : i ∈ s
hnz : ∀ (a : F), x - (algebraMap F E) a ≠ 0
b : E := ∏ j ∈ s, (x - (algebraMap F E) j)
h1 : ∀ i ∈ s, m i • (b * (x - (algebraMap F E) i)⁻¹) = m i • ∏ j ∈ s.erase i, (x - (algebraMap F E) j)
p : F[X] := ∑ i ∈ s, C (m i) * ∏ j ∈ s.erase i, (X - C j)
hm : (aeval i) p = (aeval i) 0
j : F
hj : j ∈ s.erase i
this : i ∈ s.erase j
⊢ m j * ∏ x ∈ s.erase j, (i - x) = 0

Tactic:
← (s.erase j).prod_erase_mul _ this,

Goal state after:
F : Type u_1
E : Type u_2
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
x : E
H : ∀ (p : F[X]), (aeval x) p = 0 → p = 0
s : Finset F
m : F → F
i : F
hi : i ∈ s
hnz : ∀ (a : F), x - (algebraMap F E) a ≠ 0
b : E := ∏ j ∈ s, (x - (algebraMap F E) j)
h1 : ∀ i ∈ s, m i • (b * (x - (algebraMap F E) i)⁻¹) = m i • ∏ j ∈ s.erase i, (x - (algebraMap F E) j)
p : F[X] := ∑ i ∈ s, C (m i) * ∏ j ∈ s.erase i, (X - C j)
hm : (aeval i) p = (aeval i) 0
j : F
hj : j ∈ s.erase i
this : i ∈ s.erase j
⊢ m j * ((∏ x ∈ (s.erase j).erase i, (i - x)) * (i - i)) = 0
Module: Mathlib.FieldTheory.KummerExtension

Goal state before:
pp: case neg
K : Type u
inst✝¹ : Field K
n : ℕ
hζ : (primitiveRoots n K).Nonempty
a : K
H : Irreducible (X ^ n - C a)
inst✝ : NeZero n
η : ↥(rootsOfUnity n K)
this✝¹ : Fact (Irreducible (X ^ n - C a))
this✝ : IsDomain K[n√a]
this : Algebra K K[n√a] := inferInstance
h : ¬a = 0
⊢ (of (X ^ n - C a)) ↑↑η * root (X ^ n - C a) / root (X ^ n - C a) = (of (X ^ n - C a)) ↑↑η

Tactic:
· exact mul_div_cancel_right₀ _ (root_X_pow_sub_C_ne_zero' (NeZero.pos n) h)

Goal state after:
Module: Mathlib.GroupTheory.CosetCover

Goal state before:
pp: case refine_3
G : Type u_1
inst✝¹ : Group G
ι : Type u_2
H : ι → Subgroup G
g : ι → G
s : Finset ι
hcovers : ⋃ i ∈ s, g i • ↑(H i) = Set.univ
inst✝ : DecidablePred FiniteIndex
D : Subgroup G := ⨅ k ∈ {i ∈ s | (H i).FiniteIndex}, H k
hD : D.FiniteIndex
hD_le : ∀ {i : ι}, i ∈ s → (H i).FiniteIndex → D ≤ H i
t : (i : ι) → i ∈ s → (H i).FiniteIndex → Finset ↥(H i)
ht :
  ∀ (i : ι) (hi : i ∈ s) (hfi : (H i).FiniteIndex),
    IsComplement ↑(t i hi hfi) ↑(D.subgroupOf (H i)) ∧ ⋃ g ∈ t i hi hfi, ↑g • ↑D = ↑(H i)
κ : Type (max u_2 u_1) := (i : ↥s) × ↥(if h : (H ↑i).FiniteIndex then t ↑i ⋯ h else {1})
f : κ → G := fun k ↦ g ↑k.fst * ↑↑k.snd
K : κ → Subgroup G := fun k ↦ if (H ↑k.fst).FiniteIndex then D else H ↑k.fst
k : κ
hkfi : (H ↑k.fst).FiniteIndex
hk : K k = D
hcovers' : ⋃ i ∈ {x | K x = D}, f i • ↑D = Set.univ
hHD : ∀ (i : ι), ¬(H i).FiniteIndex → H i ≠ D
hdensity : ∑ i ∈ s, (↑(H i).index)⁻¹ = ↑{x | K x = D}.card * (↑D.index)⁻¹
h : {x | K x = D}.card = D.index
i : ι
hi : i ∈ {x | x ∈ s ∧ (H x).FiniteIndex}
j : ι
hj : j ∈ {x | x ∈ s ∧ (H x).FiniteIndex}
hij : i ≠ j
c : Set G
hi' : c ⊆ (fun i ↦ g i • ↑(H i)) i
hj' : c ⊆ (fun i ↦ g i • ↑(H i)) j
x : G
hx : x ∈ c
hdisjoint : (↑{x | K x = D}).PairwiseDisjoint fun x ↦ f x • ↑D
⊢ x ∈ ⊥

Tactic:
rw [Set.mem_ofPred_eq] at hi hj

Goal state after:
case refine_3
G : Type u_1
inst✝¹ : Group G
ι : Type u_2
H : ι → Subgroup G
g : ι → G
s : Finset ι
hcovers : ⋃ i ∈ s, g i • ↑(H i) = Set.univ
inst✝ : DecidablePred FiniteIndex
D : Subgroup G := ⨅ k ∈ {i ∈ s | (H i).FiniteIndex}, H k
hD : D.FiniteIndex
hD_le : ∀ {i : ι}, i ∈ s → (H i).FiniteIndex → D ≤ H i
t : (i : ι) → i ∈ s → (H i).FiniteIndex → Finset ↥(H i)
ht :
  ∀ (i : ι) (hi : i ∈ s) (hfi : (H i).FiniteIndex),
    IsComplement ↑(t i hi hfi) ↑(D.subgroupOf (H i)) ∧ ⋃ g ∈ t i hi hfi, ↑g • ↑D = ↑(H i)
κ : Type (max u_2 u_1) := (i : ↥s) × ↥(if h : (H ↑i).FiniteIndex then t ↑i ⋯ h else {1})
f : κ → G := fun k ↦ g ↑k.fst * ↑↑k.snd
K : κ → Subgroup G := fun k ↦ if (H ↑k.fst).FiniteIndex then D else H ↑k.fst
k : κ
hkfi : (H ↑k.fst).FiniteIndex
hk : K k = D
hcovers' : ⋃ i ∈ {x | K x = D}, f i • ↑D = Set.univ
hHD : ∀ (i : ι), ¬(H i).FiniteIndex → H i ≠ D
hdensity : ∑ i ∈ s, (↑(H i).index)⁻¹ = ↑{x | K x = D}.card * (↑D.index)⁻¹
h : {x | K x = D}.card = D.index
i : ι
hi : i ∈ s ∧ (H i).FiniteIndex
j : ι
hj : j ∈ s ∧ (H j).FiniteIndex
hij : i ≠ j
c : Set G
hi' : c ⊆ (fun i ↦ g i • ↑(H i)) i
hj' : c ⊆ (fun i ↦ g i • ↑(H i)) j
x : G
hx : x ∈ c
hdisjoint : (↑{x | K x = D}).PairwiseDisjoint fun x ↦ f x • ↑D
⊢ x ∈ ⊥
Module: Mathlib.FieldTheory.Minpoly.ConjRootClass

Goal state before:
pp: case h.h
K : Type u_1
L : Type u_2
inst✝² : Field K
inst✝¹ : Field L
inst✝ : Algebra K L
x y : L
H : ∀ (x_1 : L), mk K x_1 = mk K x ↔ mk K x_1 = mk K y
⊢ mk K x = mk K y

Tactic:
← H

Goal state after:
case h.h
K : Type u_1
L : Type u_2
inst✝² : Field K
inst✝¹ : Field L
inst✝ : Algebra K L
x y : L
H : ∀ (x_1 : L), mk K x_1 = mk K x ↔ mk K x_1 = mk K y
⊢ mk K x = mk K x
Module: Mathlib.FieldTheory.PurelyInseparable.PerfectClosure

Goal state before:
pp: F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
⊢ IsPurelyInseparable F E ↔ perfectClosure F E = ⊤

Tactic:
isPurelyInseparable_iff_pow_mem F (ringExpChar F)

Goal state after:
F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
⊢ (∀ (x : E), ∃ n, x ^ ringExpChar F ^ n ∈ (algebraMap F E).range) ↔ perfectClosure F E = ⊤
Module: Mathlib.FieldTheory.PurelyInseparable.PerfectClosure

Goal state before:
pp: F : Type u
E : Type v
inst✝⁴ : Field F
inst✝³ : Field E
inst✝² : Algebra F E
K : Type w
inst✝¹ : Field K
inst✝ : Algebra F K
⊢ IsPurelyInseparable F ↥(perfectClosure F E)

Tactic:
isPurelyInseparable_iff_pow_mem F (ringExpChar F)

Goal state after:
F : Type u
E : Type v
inst✝⁴ : Field F
inst✝³ : Field E
inst✝² : Algebra F E
K : Type w
inst✝¹ : Field K
inst✝ : Algebra F K
⊢ ∀ (x : ↥(perfectClosure F E)), ∃ n, x ^ ringExpChar F ^ n ∈ (algebraMap F ↥(perfectClosure F E)).range
Module: Mathlib.FieldTheory.PurelyInseparable.PerfectClosure

Goal state before:
pp: F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
L : IntermediateField F E
h : IsPurelyInseparable F ↥L
⊢ L ≤ perfectClosure F E

Tactic:
isPurelyInseparable_iff_pow_mem F (ringExpChar F)

Goal state after:
F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
L : IntermediateField F E
h : ∀ (x : ↥L), ∃ n, x ^ ringExpChar F ^ n ∈ (algebraMap F ↥L).range
⊢ L ≤ perfectClosure F E
Module: Mathlib.FieldTheory.PurelyInseparable.PerfectClosure

Goal state before:
pp: F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
x : E
⊢ IsPurelyInseparable F ↥F⟮x⟯ ↔ (minpoly F x).natSepDegree = 1

Tactic:
← le_perfectClosure_iff,

Goal state after:
F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
x : E
⊢ F⟮x⟯ ≤ perfectClosure F E ↔ (minpoly F x).natSepDegree = 1
Module: Mathlib.FieldTheory.PurelyInseparable.PerfectClosure

Goal state before:
pp: F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
q : ℕ
hF : ExpChar F q
x : E
⊢ IsPurelyInseparable F ↥F⟮x⟯ ↔ ∃ n, x ^ q ^ n ∈ (algebraMap F E).range

Tactic:
← le_perfectClosure_iff,

Goal state after:
F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
q : ℕ
hF : ExpChar F q
x : E
⊢ F⟮x⟯ ≤ perfectClosure F E ↔ ∃ n, x ^ q ^ n ∈ (algebraMap F E).range
Module: Mathlib.FieldTheory.PurelyInseparable.PerfectClosure

Goal state before:
pp: F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
q : ℕ
hF : ExpChar F q
S : Set E
⊢ IsPurelyInseparable F ↥(adjoin F S) ↔ ∀ x ∈ S, ∃ n, x ^ q ^ n ∈ (algebraMap F E).range

Tactic:
← le_perfectClosure_iff,

Goal state after:
F : Type u
E : Type v
inst✝² : Field F
inst✝¹ : Field E
inst✝ : Algebra F E
q : ℕ
hF : ExpChar F q
S : Set E
⊢ adjoin F S ≤ perfectClosure F E ↔ ∀ x ∈ S, ∃ n, x ^ q ^ n ∈ (algebraMap F E).range
Module: Mathlib.FieldTheory.PurelyInseparable.PerfectClosure

Goal state before:
pp: F : Type u
E : Type v
inst✝⁴ : Field F
inst✝³ : Field E
inst✝² : Algebra F E
q n : ℕ
hF : ExpChar F q
ι : Type u_1
v : ι → E
inst✝¹ : FiniteDimensional F E
inst✝ : Algebra.IsSeparable F E
h : LinearIndependent F v
h' : LinearIndepOn F id (Set.range v)
ι' : Set E := h'.extend ⋯
b : Basis (↑ι') F E := Basis.extend h'
this : Fintype ↑ι' := FiniteDimensional.fintypeBasisIndex b
H : LinearIndependent F fun (x : ↑ι') ↦ b x ^ q ^ n
f : ι → ↑ι' := fun i ↦ ⟨v i, ⋯⟩
⊢ LinearIndependent F fun x ↦ v x ^ q ^ n

Tactic:
convert! H.comp f fun _ _ heq ↦ h.injective (by simpa only [f, Subtype.mk.injEq] using heq)

Goal state after:
F : Type u
E : Type v
inst✝⁴ : Field F
inst✝³ : Field E
inst✝² : Algebra F E
q n : ℕ
hF : ExpChar F q
ι : Type u_1
v : ι → E
inst✝¹ : FiniteDimensional F E
inst✝ : Algebra.IsSeparable F E
h : LinearIndependent F v
h' : LinearIndepOn F id (Set.range v)
ι' : Set E := h'.extend ⋯
b : Basis (↑ι') F E := Basis.extend h'
this : Fintype ↑ι' := FiniteDimensional.fintypeBasisIndex b
H : LinearIndependent F fun (x : ↑ι') ↦ b x ^ q ^ n
f : ι → ↑ι' := fun i ↦ ⟨v i, ⋯⟩
x✝ : ι
⊢ v x✝ ^ q ^ n = ((fun x ↦ b x ^ q ^ n) ∘ f) x✝
Module: Mathlib.FieldTheory.RatFunc.Degree

Goal state before:
pp: K : Type u
inst✝ : Field K
x y : K⟮X⟯
hx : x ≠ 0
hy : y ≠ 0
⊢ (x * y).num.natDegree + (x.denom.natDegree + y.denom.natDegree) =
    x.num.natDegree + y.num.natDegree + (x * y).denom.natDegree

Tactic:
rw [← Polynomial.natDegree_mul x.denom_ne_zero y.denom_ne_zero, ←
    Polynomial.natDegree_mul (RatFunc.num_ne_zero (mul_ne_zero hx hy))
      (mul_ne_zero x.denom_ne_zero y.denom_ne_zero),
    ← Polynomial.natDegree_mul (RatFunc.num_ne_zero hx) (RatFunc.num_ne_zero hy), ←
    Polynomial.natDegree_mul (mul_ne_zero (RatFunc.num_ne_zero hx) (RatFunc.num_ne_zero hy))
      (x * y).denom_ne_zero,
    RatFunc.num_denom_mul]

Goal state after:
Module: Mathlib.FieldTheory.RatFunc.IntermediateField

Goal state before:
pp: K : Type u_1
inst✝ : Field K
f : K⟮X⟯
hf : ¬∃ c, f = C c
f_ne_zero : f ≠ 0
⊢ f.num.natDegree ≤ (f.minpolyX ↥K⟮f⟯).natDegree

Tactic:
apply le_natDegree_of_ne_zero

Goal state after:
K : Type u_1
inst✝ : Field K
f : K⟮X⟯
hf : ¬∃ c, f = C c
f_ne_zero : f ≠ 0
⊢ (f.minpolyX ↥K⟮f⟯).coeff f.num.natDegree ≠ 0
Module: Mathlib.FieldTheory.RatFunc.IntermediateField

Goal state before:
pp: case neg.a
K : Type u_1
inst✝ : Field K
f : K⟮X⟯
hf : ¬∃ c, f = C c
⊢ (f.minpolyX ↥K⟮f⟯).natDegree ≤ max f.num.natDegree f.denom.natDegree

Tactic:
have : (f.minpolyX K⟮f⟯).natDegree ≤ _ := natDegree_sub_le _ _
    rw [natDegree_map, natDegree_C_mul fun H ↦ hf ⟨0, by simpa [map_zero] using congr($(H).val)⟩,
      natDegree_map] at this
    exact this

Goal state after:
Module: Mathlib.FieldTheory.RatFunc.IntermediateField

Goal state before:
pp: K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
hE : ∃ x ∈ E, x ∉ ⊥
⊢ IsAlgebraic (↥E) X

Tactic:
obtain ⟨f, hf₁, hf₂⟩ := hE

Goal state after:
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
f : K⟮X⟯
hf₁ : f ∈ E
hf₂ : f ∉ ⊥
⊢ IsAlgebraic (↥E) X
Module: Mathlib.FieldTheory.RatFunc.Luroth

Goal state before:
pp: case h
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
⊢ generator E = (algebraMap K[X] K⟮X⟯) ((Φ E).coeff (generatorIndex h)) / (algebraMap K[X] K⟮X⟯) (c E).num

Tactic:
Φ_coeff_generatorIndex h,

Goal state after:
case h
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
⊢ generator E = (algebraMap K[X] K⟮X⟯) (c E).num * generator E / (algebraMap K[X] K⟮X⟯) (c E).num
Module: Mathlib.FieldTheory.RatFunc.Luroth

Goal state before:
pp: K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
⊢ Φ E ≠ 0

Tactic:
intro H
  have := Φ_coeff_φ_natDegree' h ▸ congr($(H).coeff (φ E).natDegree)
  rw [coeff_zero] at this
  exact num_ne_zero (c_ne_zero h) this

Goal state after:
Module: Mathlib.FieldTheory.RatFunc.Luroth

Goal state before:
pp: K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
⊢ Polynomial.map Polynomial.C (Q₂ h) = Q₁ h

Tactic:
have := eq_C_of_natDegree_eq_zero (swap_Q₁_natDegree h)

Goal state after:
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
this : Bivariate.swap (Q₁ h) = Polynomial.C ((Bivariate.swap (Q₁ h)).coeff 0)
⊢ Polynomial.map Polynomial.C (Q₂ h) = Q₁ h
Module: Mathlib.FieldTheory.RatFunc.Luroth

Goal state before:
pp: K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
H : ¬(Q₂ h).natDegree = 0
F : Type u_1 := AlgebraicClosure K
⊢ (generator E).num.natDegree = 0 ∧ (generator E).denom.natDegree = 0

Tactic:
natDegree_eq_zero_iff_degree_le_zero.not,

Goal state after:
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
H : ¬(Q₂ h).degree ≤ 0
F : Type u_1 := AlgebraicClosure K
⊢ (generator E).num.natDegree = 0 ∧ (generator E).denom.natDegree = 0
Module: Mathlib.FieldTheory.RatFunc.Luroth

Goal state before:
pp: case inl
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
F : Type u_1 := AlgebraicClosure K
H✝ : ¬(Polynomial.map (algebraMap K F) (Q₂ h)).degree ≤ 0
α : F
hα : (aeval α) (Q₂ h) = 0
eq :
  (Polynomial.mapRingHom (algebraMap K F)) (g E) * Polynomial.C ((aeval α) (f E)) =
    (Polynomial.mapRingHom (algebraMap K F)) (f E) * Polynomial.C ((aeval α) (g E))
H : (aeval α) (generator E).num ≠ 0
⊢ (aeval α) (f E) ≠ 0 ∧ (aeval α) (g E) ≠ 0

pp: case inr
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
F : Type u_1 := AlgebraicClosure K
H✝ : ¬(Polynomial.map (algebraMap K F) (Q₂ h)).degree ≤ 0
α : F
hα : (aeval α) (Q₂ h) = 0
eq :
  (Polynomial.mapRingHom (algebraMap K F)) (g E) * Polynomial.C ((aeval α) (f E)) =
    (Polynomial.mapRingHom (algebraMap K F)) (f E) * Polynomial.C ((aeval α) (g E))
H : (aeval α) (generator E).denom ≠ 0
⊢ (aeval α) (f E) ≠ 0 ∧ (aeval α) (g E) ≠ 0

Tactic:
· refine ⟨H, Polynomial.C_injective.ne_iff.mp ?_⟩
      rw [map_zero, ← mul_ne_zero_iff_left <| Polynomial.map_ne_zero <|
        num_ne_zero (generator_ne_zero h)]
      exact eq ▸ mul_ne_zero (Polynomial.map_ne_zero (generator E).denom_ne_zero) <|
        Polynomial.C_ne_zero.mpr H

Goal state after:
case inr
K : Type u_1
inst✝ : Field K
E : IntermediateField K K⟮X⟯
h : E ≠ ⊥
F : Type u_1 := AlgebraicClosure K
H✝ : ¬(Polynomial.map (algebraMap K F) (Q₂ h)).degree ≤ 0
α : F
hα : (aeval α) (Q₂ h) = 0
eq :
  (Polynomial.mapRingHom (algebraMap K F)) (g E) * Polynomial.C ((aeval α) (f E)) =
    (Polynomial.mapRingHom (algebraMap K F)) (f E) * Polynomial.C ((aeval α) (g E))
H : (aeval α) (generator E).denom ≠ 0
⊢ (aeval α) (f E) ≠ 0 ∧ (aeval α) (g E) ≠ 0