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

Goal state before:
pp: L : Language
α : Type u'
φ : (n : ℕ) × L.BoundedFormula α n
h : listDecode (flatMap (fun φ ↦ φ.snd.listEncode) [φ]) = [φ]
⊢ (listDecode φ.snd.listEncode)[0]? = some φ

Tactic:
rw [flatMap_singleton] at h

Goal state after:
L : Language
α : Type u'
φ : (n : ℕ) × L.BoundedFormula α n
h : listDecode φ.snd.listEncode = [φ]
⊢ (listDecode φ.snd.listEncode)[0]? = some φ
Module: Mathlib.ModelTheory.Encoding

Goal state before:
pp: L : Language
α : Type u'
⊢ ℵ₀ + (lift.{max (max u v) (max u u') v, u'} #α + lift.{max (max u' v) (max u u') v, u} #((i : ℕ) × L.Functions i)) +
      (lift.{max (max u u') v, v} #((n : ℕ) × L.Relations n) + ℵ₀) ≤
    max ℵ₀ (lift.{max (max u v) (max u u') v, u'} #α + lift.{max u' (max u u') v, max u v} L.card)

Tactic:
rw [← add_assoc, add_comm, ← add_assoc, ← add_assoc, aleph0_add_aleph0, add_assoc,
    add_eq_max le_rfl, add_assoc, card, Symbols, mk_sum, lift_add, lift_lift, lift_lift]

Goal state after:
Module: Mathlib.ModelTheory.Algebra.Field.IsAlgClosed

Goal state before:
pp: p : ℕ
κ : Cardinal.{u_2}
hκ : ℵ₀ < κ
M : Type u_2
struc✝¹ : Language.ring.Structure M
is_model✝¹ : M ⊨ Theory.ACF p
nonempty'✝¹ : Nonempty M
N : Type u_2
struc✝ : Language.ring.Structure N
is_model✝ : N ⊨ Theory.ACF p
nonempty'✝ : Nonempty N
hM : #↑{ Carrier := M, struc := struc✝¹, is_model := is_model✝¹, nonempty' := nonempty'✝¹ } = κ
hN : #↑{ Carrier := N, struc := struc✝, is_model := is_model✝, nonempty' := nonempty'✝ } = κ
x✝² : Field M := fieldOfModelACF p M
this✝¹ : M ⊨ Theory.field
x✝¹ : CompatibleRing M := compatibleRingOfModelField M
this✝ : IsAlgClosed M
this : CharP M p
x✝ : Field N := fieldOfModelACF p N
⊢ Nonempty
    (↑{ Carrier := M, struc := struc✝¹, is_model := is_model✝¹, nonempty' := nonempty'✝¹ } ≃[Language.ring]
      ↑{ Carrier := N, struc := struc✝, is_model := is_model✝, nonempty' := nonempty'✝ })

Tactic:
have := modelField_of_modelACF p N

Goal state after:
p : ℕ
κ : Cardinal.{u_2}
hκ : ℵ₀ < κ
M : Type u_2
struc✝¹ : Language.ring.Structure M
is_model✝¹ : M ⊨ Theory.ACF p
nonempty'✝¹ : Nonempty M
N : Type u_2
struc✝ : Language.ring.Structure N
is_model✝ : N ⊨ Theory.ACF p
nonempty'✝ : Nonempty N
hM : #↑{ Carrier := M, struc := struc✝¹, is_model := is_model✝¹, nonempty' := nonempty'✝¹ } = κ
hN : #↑{ Carrier := N, struc := struc✝, is_model := is_model✝, nonempty' := nonempty'✝ } = κ
x✝² : Field M := fieldOfModelACF p M
this✝² : M ⊨ Theory.field
x✝¹ : CompatibleRing M := compatibleRingOfModelField M
this✝¹ : IsAlgClosed M
this✝ : CharP M p
x✝ : Field N := fieldOfModelACF p N
this : N ⊨ Theory.field
⊢ Nonempty
    (↑{ Carrier := M, struc := struc✝¹, is_model := is_model✝¹, nonempty' := nonempty'✝¹ } ≃[Language.ring]
      ↑{ Carrier := N, struc := struc✝, is_model := is_model✝, nonempty' := nonempty'✝ })
Module: Mathlib.ModelTheory.Satisfiability

Goal state before:
pp: L : Language
T : L.Theory
h : T.IsComplete
M : Type u_1
N : Type u_2
inst✝⁵ : L.Structure M
inst✝⁴ : L.Structure N
inst✝³ : M ⊨ T
inst✝² : N ⊨ T
inst✝¹ : Nonempty M
inst✝ : Nonempty N
⊢ L.completeTheory M = L.completeTheory N

Tactic:
← h.eq_complete_theory,

Goal state after:
L : Language
T : L.Theory
h : T.IsComplete
M : Type u_1
N : Type u_2
inst✝⁵ : L.Structure M
inst✝⁴ : L.Structure N
inst✝³ : M ⊨ T
inst✝² : N ⊨ T
inst✝¹ : Nonempty M
inst✝ : Nonempty N
⊢ {φ | T ⊨ᵇ φ} = L.completeTheory N
Module: Mathlib.SetTheory.Cardinal.Divisibility

Goal state before:
pp: n m : ℕ
⊢ ↑n ∣ ↑m → n ∣ m

Tactic:
rintro ⟨k, hk⟩

Goal state after:
n m : ℕ
k : Cardinal.{u_1}
hk : ↑m = ↑n * k
⊢ n ∣ m
Module: Mathlib.SetTheory.Cardinal.Divisibility

Goal state before:
pp: case refine_3.inr
n : ℕ
h : ∀ (a b : ℕ), n ∣ a * b → n ∣ a ∨ n ∣ b
b c : Cardinal.{u_1}
hbc : ↑n ∣ b * c
h' : ℵ₀ ≤ b * c
hb : b ≠ 0
hc : c ≠ 0
hℵ₀ : ℵ₀ ≤ b ∨ ℵ₀ ≤ c
⊢ ↑n ∣ b ∨ ↑n ∣ c

Tactic:
have hn : (n : Cardinal) ≠ 0 := by
    intro h
    rw [h, zero_dvd_iff, mul_eq_zero] at hbc
    cases hbc <;> contradiction

Goal state after:
case refine_3.inr
n : ℕ
h : ∀ (a b : ℕ), n ∣ a * b → n ∣ a ∨ n ∣ b
b c : Cardinal.{u_1}
hbc : ↑n ∣ b * c
h' : ℵ₀ ≤ b * c
hb : b ≠ 0
hc : c ≠ 0
hℵ₀ : ℵ₀ ≤ b ∨ ℵ₀ ≤ c
hn : ↑n ≠ 0
⊢ ↑n ∣ b ∨ ↑n ∣ c
Module: Mathlib.FieldTheory.Finite.Extension

Goal state before:
pp: case succ
k : Type u_1
inst✝⁴ : Field k
inst✝³ : Finite k
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP k p
n : ℕ
inst✝ : NeZero n
i : ℕ
ih : ∀ {x : Extension k p n}, (frob k p n ^ i) x = x ^ Nat.card k ^ i
x : Extension k p n
⊢ (frob k p n ^ i * frob k p n) x = x ^ Nat.card k ^ (i + 1)

Tactic:
AlgEquiv.mul_apply,

Goal state after:
case succ
k : Type u_1
inst✝⁴ : Field k
inst✝³ : Finite k
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : CharP k p
n : ℕ
inst✝ : NeZero n
i : ℕ
ih : ∀ {x : Extension k p n}, (frob k p n ^ i) x = x ^ Nat.card k ^ i
x : Extension k p n
⊢ (frob k p n ^ i) ((frob k p n) x) = x ^ Nat.card k ^ (i + 1)
Module: Mathlib.FieldTheory.Differential.Liouville

Goal state before:
pp: F : Type u_1
K : Type u_2
inst✝¹² : Field F
inst✝¹¹ : Field K
inst✝¹⁰ : Differential F
inst✝⁹ : Differential K
inst✝⁸ : Algebra F K
inst✝⁷ : DifferentialAlgebra F K
A : Type u_3
inst✝⁶ : Field A
inst✝⁵ : Algebra K A
inst✝⁴ : Algebra F A
inst✝³ : Differential A
inst✝² : IsScalarTower F K A
inst✝¹ : ContainConstants F K
inst1 : IsLiouville F K
inst2 : IsLiouville K A
a : F
ι : Type
inst✝ : Fintype ι
c : ι → F
hc✝ : ∀ (x : ι), (c x)′ = 0
u : ι → A
v : A
h : ↑a = ∑ x, ↑(c x) * logDeriv (u x) + v′
ι₀ : Type
w✝ : Fintype ι₀
c₀✝ : ι₀ → K
hc₀ : ∀ (x : ι₀), (c₀✝ x)′ = 0
u₀ : ι₀ → K
v₀ : K
h₀ : ↑a = ∑ x, c₀✝ x * logDeriv (u₀ x) + v₀′
c₀ : ι₀ → F
hc : ∀ (x : ι₀), (algebraMap F K) (c₀ x) = c₀✝ x
⊢ ∃ ι₀ x c₀, ∃ (_ : ∀ (x : ι₀), (c₀ x)′ = 0), ∃ u₀ v₀, a = ∑ x, c₀ x * logDeriv (u₀ x) + v₀′

Tactic:
apply inst1.isLiouville a ι₀ c₀ _ u₀ v₀

Goal state after:
F : Type u_1
K : Type u_2
inst✝¹² : Field F
inst✝¹¹ : Field K
inst✝¹⁰ : Differential F
inst✝⁹ : Differential K
inst✝⁸ : Algebra F K
inst✝⁷ : DifferentialAlgebra F K
A : Type u_3
inst✝⁶ : Field A
inst✝⁵ : Algebra K A
inst✝⁴ : Algebra F A
inst✝³ : Differential A
inst✝² : IsScalarTower F K A
inst✝¹ : ContainConstants F K
inst1 : IsLiouville F K
inst2 : IsLiouville K A
a : F
ι : Type
inst✝ : Fintype ι
c : ι → F
hc✝ : ∀ (x : ι), (c x)′ = 0
u : ι → A
v : A
h : ↑a = ∑ x, ↑(c x) * logDeriv (u x) + v′
ι₀ : Type
w✝ : Fintype ι₀
c₀✝ : ι₀ → K
hc₀ : ∀ (x : ι₀), (c₀✝ x)′ = 0
u₀ : ι₀ → K
v₀ : K
h₀ : ↑a = ∑ x, c₀✝ x * logDeriv (u₀ x) + v₀′
c₀ : ι₀ → F
hc : ∀ (x : ι₀), (algebraMap F K) (c₀ x) = c₀✝ x
⊢ ↑a = ∑ x, ↑(c₀ x) * logDeriv (u₀ x) + v₀′

F : Type u_1
K : Type u_2
inst✝¹² : Field F
inst✝¹¹ : Field K
inst✝¹⁰ : Differential F
inst✝⁹ : Differential K
inst✝⁸ : Algebra F K
inst✝⁷ : DifferentialAlgebra F K
A : Type u_3
inst✝⁶ : Field A
inst✝⁵ : Algebra K A
inst✝⁴ : Algebra F A
inst✝³ : Differential A
inst✝² : IsScalarTower F K A
inst✝¹ : ContainConstants F K
inst1 : IsLiouville F K
inst2 : IsLiouville K A
a : F
ι : Type
inst✝ : Fintype ι
c : ι → F
hc✝ : ∀ (x : ι), (c x)′ = 0
u : ι → A
v : A
h : ↑a = ∑ x, ↑(c x) * logDeriv (u x) + v′
ι₀ : Type
w✝ : Fintype ι₀
c₀✝ : ι₀ → K
hc₀ : ∀ (x : ι₀), (c₀✝ x)′ = 0
u₀ : ι₀ → K
v₀ : K
h₀ : ↑a = ∑ x, c₀✝ x * logDeriv (u₀ x) + v₀′
c₀ : ι₀ → F
hc : ∀ (x : ι₀), (algebraMap F K) (c₀ x) = c₀✝ x
⊢ ∀ (x : ι₀), (c₀ x)′ = 0
Module: Mathlib.Topology.Separation.Connected

Goal state before:
pp: X : Type u_1
inst✝ : TopologicalSpace X
h : TotallyDisconnectedSpace X
x : X
⊢ IsClosed[inst✝] {x}

Tactic:
rw [← totallyDisconnectedSpace_iff_connectedComponent_singleton.mp h x]

Goal state after:
X : Type u_1
inst✝ : TopologicalSpace X
h : TotallyDisconnectedSpace X
x : X
⊢ IsClosed[inst✝] (connectedComponent x)
Module: Mathlib.FieldTheory.CardinalEmb

Goal state before:
pp: F : Type u
E : Type v
inst✝⁴ : Field F
inst✝³ : Field E
inst✝² : Algebra F E
rank_inf : Fact (ℵ₀ ≤ Module.rank F E)
inst✝¹ : Algebra.IsAlgebraic F E
inst✝ : Algebra.IsSeparable F E
i : (Module.rank F E).ord.ToType
this : finrank ↥(adjoin F (⇑b ∘ φ '' Iio i)) ↥(↥(adjoin F (⇑b ∘ φ '' Iio i)))⟮b (φ i)⟯ ≤ 1
⊢ False

Tactic:
obtain ⟨x, hx⟩ := finrank_adjoin_simple_eq_one_iff.mp (this.antisymm Module.finrank_pos)

Goal state after:
F : Type u
E : Type v
inst✝⁴ : Field F
inst✝³ : Field E
inst✝² : Algebra F E
rank_inf : Fact (ℵ₀ ≤ Module.rank F E)
inst✝¹ : Algebra.IsAlgebraic F E
inst✝ : Algebra.IsSeparable F E
i : (Module.rank F E).ord.ToType
this : finrank ↥(adjoin F (⇑b ∘ φ '' Iio i)) ↥(↥(adjoin F (⇑b ∘ φ '' Iio i)))⟮b (φ i)⟯ ≤ 1
x : ↥(adjoin F (⇑b ∘ φ '' Iio i))
hx : (Algebra.ofId (↥(adjoin F (⇑b ∘ φ '' Iio i))) E).toRingHom x = b (φ i)
⊢ False
Module: Mathlib.FieldTheory.Galois.Profinite

Goal state before:
pp: k : Type u_3
K : Type u_4
inst✝² : Field k
inst✝¹ : Field K
inst✝ : Algebra k K
L : FiniteGaloisIntermediateField k K
g : ↑(limit (asProfiniteGaloisGroupFunctor k K)).toProfinite.toTop
x : ↥L.toIntermediateField
L' : FiniteGaloisIntermediateField k K
h : L ≤ L'
⊢ ↑(((proj L) g) x) = ↑(((proj L') g) ⟨↑x, ⋯⟩)

Tactic:
induction L with | _ L => ?_

Goal state after:
case mk
k : Type u_3
K : Type u_4
inst✝² : Field k
inst✝¹ : Field K
inst✝ : Algebra k K
g : ↑(limit (asProfiniteGaloisGroupFunctor k K)).toProfinite.toTop
L' : FiniteGaloisIntermediateField k K
L : IntermediateField k K
finiteDimensional✝ : FiniteDimensional k ↥L
isGalois✝ : IsGalois k ↥L
x : ↥{ toIntermediateField := L, finiteDimensional := finiteDimensional✝, isGalois := isGalois✝ }.toIntermediateField
h : { toIntermediateField := L, finiteDimensional := finiteDimensional✝, isGalois := isGalois✝ } ≤ L'
⊢ ↑(((proj { toIntermediateField := L, finiteDimensional := finiteDimensional✝, isGalois := isGalois✝ }) g) x) =
    ↑(((proj L') g) ⟨↑x, ⋯⟩)
Module: Mathlib.FieldTheory.PerfectClosure

Goal state before:
pp: case mp.symm
K : Type u
inst✝² : CommRing K
p : ℕ
inst✝¹ : Fact (Nat.Prime p)
inst✝ : CharP K p
x✝ y✝ x y : ℕ × K
H : Relation.EqvGen (R K p) x y
w : ℕ
ih : (⇑(frobenius K p))^[y.1 + w] x.2 = (⇑(frobenius K p))^[x.1 + w] y.2
⊢ ∃ z, (⇑(frobenius K p))^[x.1 + z] y.2 = (⇑(frobenius K p))^[y.1 + z] x.2

Tactic:
exact ⟨w, ih.symm⟩

Goal state after:
Module: Mathlib.FieldTheory.Galois.Profinite

Goal state before:
pp: k✝ : Type u_1
K✝ : Type u_2
inst✝⁶ : Field k✝
inst✝⁵ : Field K✝
inst✝⁴ : Algebra k✝ K✝
k : Type u_3
K : Type u_4
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
inst✝ : IsGalois k K
g : ↑(limit (asProfiniteGaloisGroupFunctor k K)).toProfinite.toTop
x : K
L : FiniteGaloisIntermediateField k K := adjoin k {x, toAlgEquivAux g⁻¹ x}
hx : x ∈ L.toIntermediateField
hx' : toAlgEquivAux g⁻¹ x ∈ L.toIntermediateField
⊢ toAlgEquivAux g (toAlgEquivAux g⁻¹ x) = x

Tactic:
simp only [toAlgEquivAux_eq_proj_of_mem _ _ L hx', mk_toAlgEquivAux g⁻¹ x L hx' hx, map_inv,
      AlgEquiv.aut_inv, AlgEquiv.apply_symm_apply]

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

Goal state before:
pp: R : Type u
inst✝¹ : Field R
inst✝ : IsRealClosed R
x : R
n : ℕ
hn : Odd n
r : R
hr : (X ^ n - C x).IsRoot r
⊢ r ^ n - x = 0

Tactic:
simpa using hr

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

Goal state before:
pp: R : Type u
inst✝¹ : Field R
inst✝ : IsRealClosed R
x : R
n : ℕ
hk : Odd (-↑n)
r : R
hr : x = r ^ n
⊢ x = r⁻¹ ^ (-↑n)

Tactic:
simpa using hr

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
n : ℕ
hk : -↑n ≠ 0
r : R
hr : x = r ^ n
⊢ x = r⁻¹ ^ (-↑n)

Tactic:
simpa using hr

Goal state after:
Module: Mathlib.GroupTheory.CosetCover

Goal state before:
pp: G : Type u_1
inst✝¹ : Group G
inst✝ : DecidableEq (Subgroup G)
n : ℕ
ih :
  ∀ m < n,
    ∀ {ι : Type u_2} {H : ι → Subgroup G} {g : ι → G} {s : Finset ι},
      ⋃ i ∈ s, g i • ↑(H i) = Set.univ →
        ∀ j ∈ s,
          ⋃ i ∈ {x ∈ s | H x = H j}, g i • ↑(H i) ≠ Set.univ →
            m = (Finset.image H s).card → ∃ i ∈ s, H i ≠ H j ∧ (H i).FiniteIndex
ι : Type u_2
H : ι → Subgroup G
g : ι → G
s : Finset ι
hcovers : ⋃ i ∈ s, g i • ↑(H i) = Set.univ
j : ι
hj : j ∈ s
hcovers' : ⋃ i ∈ {x ∈ s | H x = H j}, g i • ↑(H i) ≠ Set.univ
hn : n = (Finset.image H s).card
x : G
hx : ∀ i ∈ s, H i = H j → ↑(g i) ≠ ↑x
y z : G
hz : z ∈ y • ↑(H j)
⊢ z ∈ ⋃ i ∈ {x ∈ s | H x ≠ H j}, (y * x⁻¹ * g i) • ↑(H i)

Tactic:
Finset.mem_filter,

Goal state after:
G : Type u_1
inst✝¹ : Group G
inst✝ : DecidableEq (Subgroup G)
n : ℕ
ih :
  ∀ m < n,
    ∀ {ι : Type u_2} {H : ι → Subgroup G} {g : ι → G} {s : Finset ι},
      ⋃ i ∈ s, g i • ↑(H i) = Set.univ →
        ∀ j ∈ s,
          ⋃ i ∈ {x ∈ s | H x = H j}, g i • ↑(H i) ≠ Set.univ →
            m = (Finset.image H s).card → ∃ i ∈ s, H i ≠ H j ∧ (H i).FiniteIndex
ι : Type u_2
H : ι → Subgroup G
g : ι → G
s : Finset ι
hcovers : ⋃ i ∈ s, g i • ↑(H i) = Set.univ
j : ι
hj : j ∈ s
hcovers' : ⋃ i ∈ {x ∈ s | H x = H j}, g i • ↑(H i) ≠ Set.univ
hn : n = (Finset.image H s).card
x : G
hx : ∀ i ∈ s, H i = H j → ↑(g i) ≠ ↑x
y z : G
hz : z ∈ y • ↑(H j)
⊢ z ∈ ⋃ i, ⋃ (_ : i ∈ s ∧ H i ≠ H j), (y * x⁻¹ * g i) • ↑(H i)
Module: Mathlib.RingTheory.MvPolynomial

Goal state before:
pp: σ : Type u
K : Type v
inst✝¹ : CommRing K
inst✝ : IsEmpty σ
⊢ Module.rank K (MvPolynomial σ K) = 1

Tactic:
by
    cases subsingleton_or_nontrivial K <;> simp [rank_eq_lift]

Goal state after:
Module: Mathlib.GroupTheory.CosetCover

Goal state before:
pp: case neg
G : Type u_1
inst✝ : 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
j : ι
hj : j ∈ s
hcovers' : ¬⋃ i ∈ {x ∈ s | H x = H j}, g i • ↑(H i) = Set.univ
i : ι
hi : i ∈ s
left✝ : H i ≠ H j
hfi : (H i).FiniteIndex
⊢ ∃ k ∈ s, (H k).FiniteIndex

Tactic:
exact ⟨i, hi, hfi⟩

Goal state after:
Module: Mathlib.FieldTheory.KummerExtension

Goal state before:
pp: case splits'
K : Type u
inst✝ : Field K
n : ℕ
hζ : (primitiveRoots n K).Nonempty
a : K
H : Irreducible (X ^ n - C a)
this✝ : Fact (Irreducible (X ^ n - C a))
this : Algebra K K[n√a] := inferInstance
⊢ (Polynomial.map (algebraMap K K[n√a]) X ^ n - Polynomial.map (algebraMap K K[n√a]) (C a)).Splits

Tactic:
Polynomial.map_C,

Goal state after:
case splits'
K : Type u
inst✝ : Field K
n : ℕ
hζ : (primitiveRoots n K).Nonempty
a : K
H : Irreducible (X ^ n - C a)
this✝ : Fact (Irreducible (X ^ n - C a))
this : Algebra K K[n√a] := inferInstance
⊢ (Polynomial.map (algebraMap K K[n√a]) X ^ n - C ((algebraMap K K[n√a]) a)).Splits
Module: Mathlib.GroupTheory.CosetCover

Goal state before:
pp: case refine_1
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
i : ι
⊢ ⋃ (_ : i ∈ {i ∈ s | (H i).FiniteIndex}), g i • ↑(H i) =
    ⋃ (hx : i ∈ s), ⋃ a, ⋃ (_ : ⟨⟨i, hx⟩, a⟩ ∈ {x | K x = D}), f ⟨⟨i, hx⟩, a⟩ • ↑D

Tactic:
Finset.mem_filter,

Goal state after:
case refine_1
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
i : ι
⊢ ⋃ (_ : i ∈ s ∧ (H i).FiniteIndex), g i • ↑(H i) =
    ⋃ (hx : i ∈ s), ⋃ a, ⋃ (_ : ⟨⟨i, hx⟩, a⟩ ∈ {x | K x = D}), f ⟨⟨i, hx⟩, a⟩ • ↑D
Module: Mathlib.FieldTheory.KummerExtension

Goal state before:
pp: case refine_2
K : Type u
inst✝⁵ : Field K
L : Type u_1
inst✝⁴ : Field L
inst✝³ : Algebra K L
inst✝² : FiniteDimensional K L
hK : (primitiveRoots (finrank K L) K).Nonempty
inst✝¹ : IsGalois K L
inst✝ : IsCyclic Gal(L/K)
ζ : K
hζ : IsPrimitiveRoot ζ (finrank K L)
σ : Gal(L/K)
hσ : Function.Surjective fun x ↦ σ ^ x
hσ' : orderOf σ = Nat.card Gal(L/K)
this : (minpoly K σ.toLinearMap).IsRoot ζ
v : L
hv : End.HasEigenvector σ.toLinearMap ζ v
hv' : ∀ (n : ℕ), (σ ^ n) v = ζ ^ n • v
⊢ K⟮v⟯ = ⊤

Tactic:
apply IsGalois.intermediateFieldEquivSubgroup.injective
    rw [map_top, eq_top_iff]
    intro σ' hσ'
    obtain ⟨n, rfl : σ ^ n = σ'⟩ := mem_powers_iff_mem_zpowers.mpr (hσ σ')
    have := hσ' ⟨v, IntermediateField.mem_adjoin_simple_self K v⟩
    simp only [AlgEquiv.smul_def, hv'] at this
    conv_rhs at this => rw [← one_smul K v]
    obtain ⟨k, rfl⟩ := hζ.dvd_of_pow_eq_one n (smul_left_injective K hv.2 this)
    rw [pow_mul, ← IsGalois.card_aut_eq_finrank, pow_card_eq_one', one_pow]
    exact one_mem _

Goal state after:
Module: Mathlib.FieldTheory.KummerExtension

Goal state before:
pp: case splits'
K : Type u
inst✝³ : Field K
L : Type u_1
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : FiniteDimensional K L
hK : (primitiveRoots (finrank K L) K).Nonempty
a : K
α : L
ha : α ^ finrank K L = (algebraMap K L) a
hα : K⟮α⟯ = ⊤
⊢ (Polynomial.map (algebraMap K L) X ^ finrank K L - Polynomial.map (algebraMap K L) (C a)).Splits

Tactic:
Polynomial.map_C,

Goal state after:
case splits'
K : Type u
inst✝³ : Field K
L : Type u_1
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : FiniteDimensional K L
hK : (primitiveRoots (finrank K L) K).Nonempty
a : K
α : L
ha : α ^ finrank K L = (algebraMap K L) a
hα : K⟮α⟯ = ⊤
⊢ (Polynomial.map (algebraMap K L) X ^ finrank K L - C ((algebraMap K L) a)).Splits
Module: Mathlib.GroupTheory.CosetCover

Goal state before:
pp: case inr
G : Type u_1
inst✝ : 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
h : ∀ i ∈ s, (H i).FiniteIndex → s.card < (H i).index
hs : s.Nonempty
hs' : 0 < s.card
hlt : ∀ i ∈ s, (↑(H i).index)⁻¹ < (↑s.card)⁻¹
⊢ ∑ i ∈ s, (↑s.card)⁻¹ = 1

Tactic:
rw [Finset.sum_const, nsmul_eq_mul, mul_inv_cancel₀ (Nat.cast_ne_zero.mpr hs'.ne')]

Goal state after:
Module: Mathlib.RingTheory.LinearDisjoint

Goal state before:
pp: R : Type u
inst✝⁸ : CommRing R
A : Type v
inst✝⁷ : CommRing A
B : Type w
inst✝⁶ : CommRing B
inst✝⁵ : Algebra R A
inst✝⁴ : Algebra R B
inst✝³ : Flat R A
inst✝² : Flat R B
inst✝¹ : Algebra.Transcendental R A
inst✝ : Algebra.Transcendental R B
H : IsField (A ⊗[R] B)
this✝ : Field (A ⊗[R] B) := H.toField
a : A
hta : Transcendental R a
b : B
htb : Transcendental R b
ha : Function.Injective ⇑(algebraMap R A)
hb : Function.Injective ⇑(algebraMap R B)
fa : A →ₐ[R] A ⊗[R] B := Algebra.TensorProduct.includeLeft
fb : B →ₐ[R] A ⊗[R] B := Algebra.TensorProduct.includeRight
hfa : Function.Injective ⇑fa
hfb : Function.Injective ⇑fb
this : IsDomain A
⊢ False

Tactic:
have := hfb.isDomain fb.toRingHom

Goal state after:
R : Type u
inst✝⁸ : CommRing R
A : Type v
inst✝⁷ : CommRing A
B : Type w
inst✝⁶ : CommRing B
inst✝⁵ : Algebra R A
inst✝⁴ : Algebra R B
inst✝³ : Flat R A
inst✝² : Flat R B
inst✝¹ : Algebra.Transcendental R A
inst✝ : Algebra.Transcendental R B
H : IsField (A ⊗[R] B)
this✝¹ : Field (A ⊗[R] B) := H.toField
a : A
hta : Transcendental R a
b : B
htb : Transcendental R b
ha : Function.Injective ⇑(algebraMap R A)
hb : Function.Injective ⇑(algebraMap R B)
fa : A →ₐ[R] A ⊗[R] B := Algebra.TensorProduct.includeLeft
fb : B →ₐ[R] A ⊗[R] B := Algebra.TensorProduct.includeRight
hfa : Function.Injective ⇑fa
hfb : Function.Injective ⇑fb
this✝ : IsDomain A
this : IsDomain B
⊢ False
Module: Mathlib.FieldTheory.NormalizedTrace

Goal state before:
pp: F : Type u_3
E : Type u_4
K : Type u_5
inst✝¹² : Field F
inst✝¹¹ : Field E
inst✝¹⁰ : Field K
inst✝⁹ : Algebra F E
inst✝⁸ : Algebra E K
inst✝⁷ : Algebra F K
inst✝⁶ : IsScalarTower F E K
inst✝⁵ : Algebra.IsIntegral F E
inst✝⁴ : Algebra.IsIntegral F K
inst✝³ : CharZero F
inst✝² : FiniteDimensional F E
inst✝¹ : Algebra.IsIntegral E K
inst✝ : CharZero E
a : K
⊢ (normalizedTrace F E) ((normalizedTrace E K) a) = (normalizedTrace F K) a

Tactic:
have : FiniteDimensional E E⟮a⟯ :=
    IntermediateField.adjoin.finiteDimensional (IsIntegral.isIntegral a)

Goal state after:
F : Type u_3
E : Type u_4
K : Type u_5
inst✝¹² : Field F
inst✝¹¹ : Field E
inst✝¹⁰ : Field K
inst✝⁹ : Algebra F E
inst✝⁸ : Algebra E K
inst✝⁷ : Algebra F K
inst✝⁶ : IsScalarTower F E K
inst✝⁵ : Algebra.IsIntegral F E
inst✝⁴ : Algebra.IsIntegral F K
inst✝³ : CharZero F
inst✝² : FiniteDimensional F E
inst✝¹ : Algebra.IsIntegral E K
inst✝ : CharZero E
a : K
this : FiniteDimensional E ↥E⟮a⟯
⊢ (normalizedTrace F E) ((normalizedTrace E K) a) = (normalizedTrace F K) a
Module: Mathlib.RingTheory.LinearDisjoint

Goal state before:
pp: R : Type u
S : Type v
inst✝⁴ : CommRing R
inst✝³ : CommRing S
inst✝² : Algebra R S
A B : Subalgebra R S
H : A.LinearDisjoint B
inst✝¹ : Free R ↥A
inst✝ : Free R ↥B
⊢ Module.rank R ↥(A ⊔ B) = Module.rank R ↥A * Module.rank R ↥B

Tactic:
nontriviality R
  rw [← rank_tensorProduct', H.mulMap.toLinearEquiv.rank_eq]

Goal state after:
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
⊢ ∀
    x ∈
      (have this := ⋯;
        Subalgebra.perfectClosure F E (ringExpChar F)).carrier,
    x⁻¹ ∈
      (have this := ⋯;
        Subalgebra.perfectClosure F E (ringExpChar F)).carrier

Tactic:
rintro x ⟨n, hx⟩

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 : E
n : ℕ
hx : x ^ ringExpChar F ^ n ∈ (algebraMap F E).rangeS
⊢ x⁻¹ ∈
    (have this := ⋯;
      Subalgebra.perfectClosure F E (ringExpChar F)).carrier
Module: Mathlib.FieldTheory.LinearDisjoint

Goal state before:
pp: F : Type u
inst✝⁴ : Field F
A : Type v
inst✝³ : Field A
B : Type w
inst✝² : Field B
inst✝¹ : Algebra F A
inst✝ : Algebra F B
M : Ideal (A ⊗[F] B)
hM : M.IsMaximal
K : Type (max v w) := A ⊗[F] B ⧸ M
this : Field K := Ideal.Quotient.field M
i : A ⊗[F] B →ₐ[F] K := IsScalarTower.toAlgHom F (A ⊗[F] B) K
fa : A →ₐ[F] K := i.comp Algebra.TensorProduct.includeLeft
fb : B →ₐ[F] K := i.comp Algebra.TensorProduct.includeRight
H : fa.range.LinearDisjoint fb.range
⊢ M = ⊥

Tactic:
Subalgebra.linearDisjoint_iff_injective

Goal state after:
F : Type u
inst✝⁴ : Field F
A : Type v
inst✝³ : Field A
B : Type w
inst✝² : Field B
inst✝¹ : Algebra F A
inst✝ : Algebra F B
M : Ideal (A ⊗[F] B)
hM : M.IsMaximal
K : Type (max v w) := A ⊗[F] B ⧸ M
this : Field K := Ideal.Quotient.field M
i : A ⊗[F] B →ₐ[F] K := IsScalarTower.toAlgHom F (A ⊗[F] B) K
fa : A →ₐ[F] K := i.comp Algebra.TensorProduct.includeLeft
fb : B →ₐ[F] K := i.comp Algebra.TensorProduct.includeRight
H : Function.Injective ⇑(fa.range.mulMap fb.range)
⊢ M = ⊥