mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.FieldTheory.Galois.Infinite

Goal state before:
pp: case refine_1
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
H : Subgroup Gal(K/k)
L : IntermediateField k K
inst✝ : Normal k ↥L
x : K
h : x ∈ ↑(fixedField H ⊓ L)
xL : x ∈ (fun x ↦ ↑x) L
σ : Gal(K/k)
⊢ σ ∈ H → ((restrictNormalHom ↥L) σ) ⟨x, xL⟩ = ⟨x, xL⟩

Tactic:
hσ

Goal state after:
case refine_1
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
H : Subgroup Gal(K/k)
L : IntermediateField k K
inst✝ : Normal k ↥L
x : K
h : x ∈ ↑(fixedField H ⊓ L)
xL : x ∈ (fun x ↦ ↑x) L
σ : Gal(K/k)
hσ : σ ∈ H
⊢ ((restrictNormalHom ↥L) σ) ⟨x, xL⟩ = ⟨x, xL⟩
Module: Mathlib.FieldTheory.Minpoly.MinpolyDiv

Goal state before:
pp: R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
i : ℕ
H : (minpolyDiv R x).coeff i ∉ R[x]
this : ∀ (j : ℕ), (minpolyDiv R x).coeff (i + j) ∉ R[x]
⊢ (minpolyDiv R x).natDegree < i + ((minpolyDiv R x).natDegree + 1)

Tactic:
· lia

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

Goal state before:
pp: case refine_2
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
H : Subgroup Gal(K/k)
L : IntermediateField k K
inst✝ : Normal k ↥L
x : K
xL : x ∈ L
h : ∀ a ∈ H, ((restrictNormalHom ↥L) a) ⟨x, xL⟩ = ⟨x, xL⟩
σ : Gal(K/k)
⊢ σ ∈ H → σ x = x

Tactic:
hσ

Goal state after:
case refine_2
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
H : Subgroup Gal(K/k)
L : IntermediateField k K
inst✝ : Normal k ↥L
x : K
xL : x ∈ L
h : ∀ a ∈ H, ((restrictNormalHom ↥L) a) ⟨x, xL⟩ = ⟨x, xL⟩
σ : Gal(K/k)
hσ : σ ∈ H
⊢ σ x = x
Module: Mathlib.FieldTheory.Galois.Infinite

Goal state before:
pp: k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
H : ClosedSubgroup Gal(K/k)
inst✝ : IsGalois k K
σ : Gal(K/k)
⊢ σ ∈ (fixedField ↑H).fixingSubgroup → σ ∈ ↑H

Tactic:
hσ

Goal state after:
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
H : ClosedSubgroup Gal(K/k)
inst✝ : IsGalois k K
σ : Gal(K/k)
hσ : σ ∈ (fixedField ↑H).fixingSubgroup
⊢ σ ∈ ↑H
Module: Mathlib.RingTheory.Polynomial.GaussLemma

Goal state before:
pp: R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsIntegrallyClosed R
p q : R[X]
hp : p.Monic
hq : q.Monic
r : K[X]
hr : Polynomial.map (algebraMap R K) p = Polynomial.map (algebraMap R K) q * r
d' : R[X]
hr' : Polynomial.map (algebraMap R K) d' = r
⊢ q ∣ p

pp: R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsIntegrallyClosed R
p q : R[X]
hp : p.Monic
hq : q.Monic
r : K[X]
hr : Polynomial.map (algebraMap R K) p = Polynomial.map (algebraMap R K) q * r
d' : R[X]
hr' : Polynomial.map (algebraMap R K) d' * C r.leadingCoeff = r
⊢ r.Monic

Tactic:
· rw [← hr', ← Polynomial.map_mul] at hr
    exact dvd_of_mul_right_eq _ (Polynomial.map_injective _ (IsFractionRing.injective R K) hr.symm)

Goal state after:
R : Type u_1
inst✝⁴ : CommRing R
K : Type u_2
inst✝³ : Field K
inst✝² : Algebra R K
inst✝¹ : IsFractionRing R K
inst✝ : IsIntegrallyClosed R
p q : R[X]
hp : p.Monic
hq : q.Monic
r : K[X]
hr : Polynomial.map (algebraMap R K) p = Polynomial.map (algebraMap R K) q * r
d' : R[X]
hr' : Polynomial.map (algebraMap R K) d' * C r.leadingCoeff = r
⊢ r.Monic
Module: Mathlib.FieldTheory.Minpoly.MinpolyDiv

Goal state before:
pp: case a
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
hx : IsIntegral R x
a✝ : Nontrivial S
⊢ Submodule.span R (Set.range (minpolyDiv R x).coeff) ≤ Subalgebra.toSubmodule R[x]

Tactic:
Submodule.span_le

Goal state after:
case a
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
hx : IsIntegral R x
a✝ : Nontrivial S
⊢ Set.range (minpolyDiv R x).coeff ⊆ ↑(Subalgebra.toSubmodule R[x])
Module: Mathlib.FieldTheory.Minpoly.MinpolyDiv

Goal state before:
pp: case a
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
hx : IsIntegral R x
a✝ : Nontrivial S
⊢ Submodule.span R ↑(Finset.image (fun x_1 ↦ x ^ x_1) (Finset.range (minpoly R x).natDegree)) ≤
    Submodule.span R (Set.range (minpolyDiv R x).coeff)

Tactic:
Submodule.span_le

Goal state after:
case a
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
hx : IsIntegral R x
a✝ : Nontrivial S
⊢ ↑(Finset.image (fun x_1 ↦ x ^ x_1) (Finset.range (minpoly R x).natDegree)) ⊆
    ↑(Submodule.span R (Set.range (minpolyDiv R x).coeff))
Module: Mathlib.FieldTheory.Minpoly.IsIntegrallyClosed

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDomain S
inst✝ : IsTorsionFree R S
r : R
hr : r ≠ 0
s : S
hs : IsIntegral R s
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
this : Algebra K L := FractionRing.liftAlgebra R L
⊢ minpoly K ((algebraMap S L) (r • s)) = (map (algebraMap R K) (minpoly R s)).scaleRoots ((algebraMap R K) r)

Tactic:
← minpoly.isIntegrallyClosed_eq_field_fractions K L hs

Goal state after:
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : IsDomain R
inst✝³ : Algebra R S
inst✝² : IsIntegrallyClosed R
inst✝¹ : IsDomain S
inst✝ : IsTorsionFree R S
r : R
hr : r ≠ 0
s : S
hs : IsIntegral R s
K : Type u_1 := FractionRing R
L : Type u_2 := FractionRing S
this : Algebra K L := FractionRing.liftAlgebra R L
⊢ minpoly K ((algebraMap S L) (r • s)) = (minpoly K ((algebraMap S L) s)).scaleRoots ((algebraMap R K) r)
Module: Mathlib.FieldTheory.Minpoly.MinpolyDiv

Goal state before:
pp: case a.ind.refine_1
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
hx : IsIntegral R x
a✝ : Nontrivial S
i : ℕ
hi :
  ∀ m < i,
    m ∈ Set.Iio (minpoly R x).natDegree →
      m ∈ (fun x_1 ↦ x ^ x_1) ⁻¹' ↑(Submodule.span R (Set.range (minpolyDiv R x).coeff))
hi' : i ∈ Set.Iio (minpoly R x).natDegree
this : (minpolyDiv R x).coeff ((minpolyDiv R x).natDegree - i) ∈ Submodule.span R (Set.range (minpolyDiv R x).coeff)
j : ℕ
⊢ j ∈ Set.Iio i → j ∈ (fun x_1 ↦ x ^ x_1) ⁻¹' ↑(Submodule.span R (Set.range (minpolyDiv R x).coeff))

Tactic:
(hj : j < i)

Goal state after:
case a.ind.refine_1
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
hx : IsIntegral R x
a✝ : Nontrivial S
i : ℕ
hi :
  ∀ m < i,
    m ∈ Set.Iio (minpoly R x).natDegree →
      m ∈ (fun x_1 ↦ x ^ x_1) ⁻¹' ↑(Submodule.span R (Set.range (minpolyDiv R x).coeff))
hi' : i ∈ Set.Iio (minpoly R x).natDegree
this : (minpolyDiv R x).coeff ((minpolyDiv R x).natDegree - i) ∈ Submodule.span R (Set.range (minpolyDiv R x).coeff)
j : ℕ
hj : j < i
⊢ j ∈ (fun x_1 ↦ x ^ x_1) ⁻¹' ↑(Submodule.span R (Set.range (minpolyDiv R x).coeff))
Module: Mathlib.FieldTheory.IsSepClosed

Goal state before:
pp: k : Type u
inst✝⁵ : Field k
K : Type v
inst✝⁴ : Field K
F : Type u_1
E : Type u_2
inst✝³ : Field F
inst✝² : Field E
inst✝¹ : Algebra F E
inst✝ : Normal F E
⊢ Normal F ↥(separableClosure F E)

Tactic:
← separableClosure.normalClosure_eq_self

Goal state after:
k : Type u
inst✝⁵ : Field k
K : Type v
inst✝⁴ : Field K
F : Type u_1
E : Type u_2
inst✝³ : Field F
inst✝² : Field E
inst✝¹ : Algebra F E
inst✝ : Normal F E
⊢ Normal F ↥(IntermediateField.normalClosure F (↥(separableClosure F E)) E)
Module: Mathlib.FieldTheory.PurelyInseparable.Basic

Goal state before:
pp: F : Type u
E : Type v
inst✝⁵ : Field F
inst✝⁴ : Field E
inst✝³ : Algebra F E
K : Type w
inst✝² : Field K
inst✝¹ : Algebra F K
inst✝ : IsPurelyInseparable F E
x : E
n : ℕ
h : Polynomial.map (algebraMap F E) (minpoly F x) = (X - C x) ^ ringExpChar F ^ n
⊢ ((X - C x) ^ ringExpChar F ^ n).Splits

Tactic:
exact Splits.pow (Splits.X_sub_C _) _

Goal state after:
Module: Mathlib.RingTheory.DedekindDomain.IntegralClosure

Goal state before:
pp: A : Type u_1
K : Type u_2
inst✝¹⁷ : CommRing A
inst✝¹⁶ : Field K
inst✝¹⁵ : Algebra A K
inst✝¹⁴ : IsFractionRing A K
L : Type u_3
inst✝¹³ : Field L
C : Type u_4
inst✝¹² : CommRing C
inst✝¹¹ : Algebra K L
inst✝¹⁰ : Algebra A L
inst✝⁹ : IsScalarTower A K L
inst✝⁸ : Algebra C L
inst✝⁷ : IsIntegralClosure C A L
inst✝⁶ : Algebra A C
inst✝⁵ : IsScalarTower A C L
inst✝⁴ : FiniteDimensional K L
inst✝³ : Algebra.IsSeparable K L
ι : Type u_5
inst✝² : Finite ι
inst✝¹ : DecidableEq ι
b : Basis ι K L
hb_int : ∀ (i : ι), IsIntegral A (b i)
inst✝ : IsIntegrallyClosed A
⊢ Submodule.span A (Set.range ⇑b) ≤ (traceForm K L).flip.dualSubmodule (↑A (Algebra.linearMap C L)).range

Tactic:
Submodule.span_le

Goal state after:
A : Type u_1
K : Type u_2
inst✝¹⁷ : CommRing A
inst✝¹⁶ : Field K
inst✝¹⁵ : Algebra A K
inst✝¹⁴ : IsFractionRing A K
L : Type u_3
inst✝¹³ : Field L
C : Type u_4
inst✝¹² : CommRing C
inst✝¹¹ : Algebra K L
inst✝¹⁰ : Algebra A L
inst✝⁹ : IsScalarTower A K L
inst✝⁸ : Algebra C L
inst✝⁷ : IsIntegralClosure C A L
inst✝⁶ : Algebra A C
inst✝⁵ : IsScalarTower A C L
inst✝⁴ : FiniteDimensional K L
inst✝³ : Algebra.IsSeparable K L
ι : Type u_5
inst✝² : Finite ι
inst✝¹ : DecidableEq ι
b : Basis ι K L
hb_int : ∀ (i : ι), IsIntegral A (b i)
inst✝ : IsIntegrallyClosed A
⊢ Set.range ⇑b ⊆ ↑((traceForm K L).flip.dualSubmodule (↑A (Algebra.linearMap C L)).range)
Module: Mathlib.FieldTheory.PurelyInseparable.Basic

Goal state before:
pp: k : Type u_1
K : Type u_2
R : Type u_3
inst✝⁶ : Field k
inst✝⁵ : Field K
inst✝⁴ : Algebra k K
inst✝³ : CommRing R
inst✝² : Algebra k R
inst✝¹ : IsPurelyInseparable k K
q : ℕ
inst✝ : ExpChar k q
x : R ⊗[k] K
⊢ ∃ n, x ^ q ^ n ∈ (algebraMap R (R ⊗[k] K)).range

Tactic:
nontriviality (R ⊗[k] K)
  obtain (hq | hq) := expChar_is_prime_or_one k q
  induction x with
  | zero => exact ⟨0, 0, by simp⟩
  | add x y h h' =>
    have : ExpChar (R ⊗[k] K) q := expChar_of_injective_ringHom (algebraMap k _).injective q
    simp_rw [RingHom.mem_range, ← RingHom.mem_rangeS, ← Subalgebra.mem_perfectClosure_iff] at h h' ⊢
    exact add_mem h h'
  | tmul x y =>
    obtain ⟨n, a, ha⟩ := IsPurelyInseparable.pow_mem k q y
    use n
    have : (x ^ q ^ n) ⊗ₜ[k] (y ^ q ^ n) =
        (x ^ q ^ n) ⊗ₜ[k] (1 : K) * (1 : R) ⊗ₜ[k] (y ^ q ^ n) := by
      rw [Algebra.TensorProduct.tmul_mul_tmul, mul_one, one_mul]
    rw [Algebra.TensorProduct.tmul_pow, this]
    refine Subring.mul_mem _ ⟨x ^ q ^ n, rfl⟩ ⟨algebraMap k R a, ?_⟩
    rw [← IsScalarTower.algebraMap_apply, Algebra.TensorProduct.algebraMap_apply,
      Algebra.TensorProduct.tmul_one_eq_one_tmul, ha]
  · subst hq
    have : CharZero k := charZero_of_expChar_one' k
    exact ⟨0, (Algebra.TensorProduct.includeLeft_surjective R _ <|
      IsPurelyInseparable.surjective_algebraMap_of_isSeparable k K) _⟩

Goal state after:
Module: Mathlib.RingTheory.IsGaloisGroup.Defs

Goal state before:
pp: G : Type u_1
A : Type u_2
A' : Type u_3
B : Type u_4
inst✝⁵ : Group G
inst✝⁴ : CommSemiring A
inst✝³ : Semiring B
inst✝² : Algebra A B
inst✝¹ : MulSemiringAction G B
hA : IsGaloisGroup G A B
inst✝ : FaithfulSMul A B
x : ↥(FixedPoints.subsemiring B G)
⊢ (fun x ↦ ⟨(algebraMap A B) x, ⋯⟩) ((fun x ↦ ⋯.choose) x) = x

Tactic:
by simpa [Subtype.ext_iff] using (hA.isInvariant.isInvariant x x.prop).choose_spec

Goal state after:
Module: Mathlib.RingTheory.Trace.Basic

Goal state before:

Tactic:
(pb.basis.toMatrix b * (pb.basis.toMatrix b)ᵀ).det *
            ((b.toMatrix pb.basis)ᵀ * b.toMatrix pb.basis).det =
          (pb.basis.toMatrix b * (b.toMatrix pb.basis * pb.basis.toMatrix b)ᵀ *
              b.toMatrix pb.basis).det := by
        simp only [← det_mul, Matrix.mul_assoc, Matrix.transpose_mul]
      _ = 1 := by
        simp only [Basis.toMatrix_mul_toMatrix_flip, Matrix.transpose_one, Matrix.mul_one,
          Matrix.det_one]

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

Goal state before:
pp: G : Type u_1
inst✝¹⁹ : Group G
A : Type u_5
B : Type u_6
C : Type u_7
inst✝¹⁸ : CommRing A
inst✝¹⁷ : CommRing B
inst✝¹⁶ : CommRing C
inst✝¹⁵ : IsDomain C
inst✝¹⁴ : Algebra A B
inst✝¹³ : Algebra A C
inst✝¹² : Algebra B C
inst✝¹¹ : FaithfulSMul A B
inst✝¹⁰ : FaithfulSMul B C
inst✝⁹ : IsScalarTower A B C
inst✝⁸ : Finite G
N : Subgroup G
inst✝⁷ : N.Normal
inst✝⁶ : MulSemiringAction G C
hG : IsGaloisGroup G A C
inst✝⁵ : MulSemiringAction G B
inst✝⁴ : MulSemiringAction (G ⧸ N) B
inst✝³ : SMulCommClass (G ⧸ N) A B
inst✝² : SMulDistribClass G B C
inst✝¹ : IsScalarTower G (G ⧸ N) B
inst✝ : IsGaloisGroup (↥N) B C
x : B
h : ∀ (g : G ⧸ N), g • x = x
g : G
this : (algebraMap B C) (↑g • x) = (algebraMap B C) x
⊢ g • (algebraMap B C) x = (algebraMap B C) x

Tactic:
rwa [MulAction.coe_quotient_smul, algebraMap.smul'] at this

Goal state after:
Module: Mathlib.RingTheory.Int.Basic

Goal state before:
pp: a b c : ℤ
hab : IsCoprime a b
k : ℕ
hk : Odd k
h : a * b = c ^ k
⊢ b * a = c ^ k

Tactic:
rwa [mul_comm] at h

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

Goal state before:
pp: G : Type u_1
K : Type u_3
L : Type u_4
inst✝⁸ : Group G
inst✝⁷ : Field K
inst✝⁶ : Field L
inst✝⁵ : Algebra K L
inst✝⁴ : MulSemiringAction G L
H : Subgroup G
F : IntermediateField K L
N : Subgroup G
inst✝³ : N.Normal
inst✝² : IsGaloisGroup (↥N) (↥F) L
E : IntermediateField K L
hE : IsGaloisGroup (↥H) (↥E) L
inst✝¹ : Finite G
inst✝ : IsGaloisGroup G K L
h : E ≤ F
this✝³ : Algebra ↥E ↥F := (IntermediateField.inclusion h).toAlgebra
this✝² : SMul G ↥F := smulOfNormal G (↥F) L N
this✝¹ : SMulDistribClass G (↥F) L
this✝ : MulSemiringAction G ↥F := mulSemiringActionOfSmulDistribClass (↥F) L G
this : IsScalarTower (↥E) (↥F) L
⊢ ∀ (m : ↥(Subgroup.map (QuotientGroup.mk' N) H)) (n : ↥E) (a : ↥F), m • n • a = n • m • a

Tactic:
intro ⟨_, g, hg, rfl⟩

Goal state after:
G : Type u_1
K : Type u_3
L : Type u_4
inst✝⁸ : Group G
inst✝⁷ : Field K
inst✝⁶ : Field L
inst✝⁵ : Algebra K L
inst✝⁴ : MulSemiringAction G L
H : Subgroup G
F : IntermediateField K L
N : Subgroup G
inst✝³ : N.Normal
inst✝² : IsGaloisGroup (↥N) (↥F) L
E : IntermediateField K L
hE : IsGaloisGroup (↥H) (↥E) L
inst✝¹ : Finite G
inst✝ : IsGaloisGroup G K L
h : E ≤ F
this✝³ : Algebra ↥E ↥F := (IntermediateField.inclusion h).toAlgebra
this✝² : SMul G ↥F := smulOfNormal G (↥F) L N
this✝¹ : SMulDistribClass G (↥F) L
this✝ : MulSemiringAction G ↥F := mulSemiringActionOfSmulDistribClass (↥F) L G
this : IsScalarTower (↥E) (↥F) L
g : G
hg : g ∈ ↑H
⊢ ∀ (n : ↥E) (a : ↥F), ⟨(QuotientGroup.mk' N) g, ⋯⟩ • n • a = n • ⟨(QuotientGroup.mk' N) g, ⋯⟩ • a
Module: Mathlib.RingTheory.Invariant.Basic

Goal state before:
pp: A : Type u_1
B : Type u_2
inst✝¹⁹ : CommRing A
inst✝¹⁸ : CommRing B
inst✝¹⁷ : Algebra A B
G : Type u_3
inst✝¹⁶ : Group G
inst✝¹⁵ : Finite G
inst✝¹⁴ : MulSemiringAction G B
inst✝¹³ : SMulCommClass G A B
P : Ideal A
Q : Ideal B
inst✝¹² : Q.IsPrime
inst✝¹¹ : Q.LiesOver P
K : Type u_4
L : Type u_5
inst✝¹⁰ : Field K
inst✝⁹ : Field L
inst✝⁸ : Algebra (A ⧸ P) K
inst✝⁷ : Algebra (B ⧸ Q) L
inst✝⁶ : Algebra (A ⧸ P) L
inst✝⁵ : IsScalarTower (A ⧸ P) (B ⧸ Q) L
inst✝⁴ : Algebra K L
inst✝³ : IsScalarTower (A ⧸ P) K L
inst✝² : Algebra.IsInvariant A B G
inst✝¹ : IsFractionRing (A ⧸ P) K
inst✝ : IsFractionRing (B ⧸ Q) L
f : Gal(L/K)
val✝ : Fintype G
this✝ : P.IsPrime
this : Algebra.IsIntegral A B
x y : B ⧸ Q
hy : y ∈ nonZeroDivisors (B ⧸ Q)
hx :
  ∀ (g : ↥(MulAction.stabilizer G Q)),
    ((IsFractionRing.stabilizerHom G P Q K L) g) ((algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y) =
      (algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y
⊢ f ((algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y) = (algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y

Tactic:
obtain ⟨b, a, ha, h⟩ := (Algebra.IsAlgebraic.isAlgebraic (R := A ⧸ P) y).exists_smul_eq_mul x hy

Goal state after:
A : Type u_1
B : Type u_2
inst✝¹⁹ : CommRing A
inst✝¹⁸ : CommRing B
inst✝¹⁷ : Algebra A B
G : Type u_3
inst✝¹⁶ : Group G
inst✝¹⁵ : Finite G
inst✝¹⁴ : MulSemiringAction G B
inst✝¹³ : SMulCommClass G A B
P : Ideal A
Q : Ideal B
inst✝¹² : Q.IsPrime
inst✝¹¹ : Q.LiesOver P
K : Type u_4
L : Type u_5
inst✝¹⁰ : Field K
inst✝⁹ : Field L
inst✝⁸ : Algebra (A ⧸ P) K
inst✝⁷ : Algebra (B ⧸ Q) L
inst✝⁶ : Algebra (A ⧸ P) L
inst✝⁵ : IsScalarTower (A ⧸ P) (B ⧸ Q) L
inst✝⁴ : Algebra K L
inst✝³ : IsScalarTower (A ⧸ P) K L
inst✝² : Algebra.IsInvariant A B G
inst✝¹ : IsFractionRing (A ⧸ P) K
inst✝ : IsFractionRing (B ⧸ Q) L
f : Gal(L/K)
val✝ : Fintype G
this✝ : P.IsPrime
this : Algebra.IsIntegral A B
x y : B ⧸ Q
hy : y ∈ nonZeroDivisors (B ⧸ Q)
hx :
  ∀ (g : ↥(MulAction.stabilizer G Q)),
    ((IsFractionRing.stabilizerHom G P Q K L) g) ((algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y) =
      (algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y
b : B ⧸ Q
a : A ⧸ P
ha : a ≠ 0
h : a • x = y * b
⊢ f ((algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y) = (algebraMap (B ⧸ Q) L) x / (algebraMap (B ⧸ Q) L) y
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: case inl
p k : ℕ
inst✝ : Fact (Nat.Prime p)
hn : 0 = p ^ k
a : ZMod 0
ha : (orderOf a).Coprime 0
⊢ a = 1 ∨ IsUnit (a - 1)

Tactic:
exact Or.inl (orderOf_eq_one_iff.mp ((orderOf a).coprime_zero_right.mp ha))

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

Goal state before:
pp: F : Type u_3
inst✝¹ : Field F
inst✝ : Fintype F
hF : ringChar F ≠ 2
a g : Fˣ
hg : ∀ (x : Fˣ), x ∈ Subgroup.zpowers g
⊢ a ∈ Subgroup.zpowers g

Tactic:
apply hg

Goal state after:
Module: Mathlib.RingTheory.FiniteStability

Goal state before:
pp: R : Type w₁
inst✝⁴ : CommRing R
A : Type w₂
inst✝³ : CommRing A
inst✝² : Algebra R A
B : Type w₃
inst✝¹ : CommRing B
inst✝ : Algebra R B
hfa : FiniteType R A
⊢ FiniteType B (B ⊗[R] A)

Tactic:
rw [iff_quotient_mvPolynomial''] at *
  obtain ⟨n, f, hf⟩ := hfa
  let g : B ⊗[R] MvPolynomial (Fin n) R →ₐ[B] B ⊗[R] A :=
    Algebra.TensorProduct.map (AlgHom.id B B) f
  have : Function.Surjective g := baseChangeAux_surj B hf
  use n, AlgHom.comp g (MvPolynomial.algebraTensorAlgEquiv R B).symm.toAlgHom
  simpa

Goal state after:
Module: Mathlib.RingTheory.Ideal.Norm.AbsNorm

Goal state before:
pp: S : Type u_1
inst✝² : CommRing S
inst✝¹ : IsDedekindDomain S
inst✝ : Free ℤ S
⊢ cardQuot 0 = 0

Tactic:
have : Infinite S := Module.Free.infinite ℤ S

Goal state after:
S : Type u_1
inst✝² : CommRing S
inst✝¹ : IsDedekindDomain S
inst✝ : Free ℤ S
this : Infinite S
⊢ cardQuot 0 = 0
Module: Mathlib.RingTheory.Ideal.Norm.AbsNorm

Goal state before:
pp: case mp
S : Type u_1
inst✝³ : CommRing S
inst✝² : IsDedekindDomain S
inst✝¹ : Free ℤ S
inst✝ : Module.Finite ℤ S
I : Ideal S
hI : absNorm I = 0
x : S
hx : x ∈ I
⊢ x ∈ ⊥

Tactic:
rw [mem_bot, ← Algebra.norm_eq_zero_iff (R := ℤ), ← Int.natAbs_eq_zero,
      ← Ideal.absNorm_span_singleton, ← zero_dvd_iff, ← hI]

Goal state after:
case mp
S : Type u_1
inst✝³ : CommRing S
inst✝² : IsDedekindDomain S
inst✝¹ : Free ℤ S
inst✝ : Module.Finite ℤ S
I : Ideal S
hI : absNorm I = 0
x : S
hx : x ∈ I
⊢ absNorm I ∣ absNorm (span {x})
Module: Mathlib.RingTheory.Ideal.Norm.AbsNorm

Goal state before:
pp: case h₃.inr
S : Type u_1
inst✝³ : CommRing S
inst✝² : IsDedekindDomain S
inst✝¹ : Free ℤ S
inst✝ : Module.Finite ℤ S
p : ℤ
hp : Prime p
this✝ : IsAddTorsionFree S
this : CharZero S
hpMax : (span {p}).IsMaximal
I P : Ideal S
hI' : I ≠ 0
hP : Prime P
IH : p ∣ ↑(absNorm I) → ∃ P, P.IsMaximal ∧ under ℤ P = span {p} ∧ P ∣ I
h : p ∣ ↑(absNorm I)
⊢ ∃ P_1, P_1.IsMaximal ∧ under ℤ P_1 = span {p} ∧ P_1 ∣ P * I

Tactic:
obtain ⟨Q, h₁, h₂, h₃⟩ := IH h
      exact ⟨Q, h₁, h₂, dvd_mul_of_dvd_right h₃ _⟩

Goal state after:
Module: Mathlib.Topology.JacobsonSpace

Goal state before:
pp: case inr
X : Type u_1
Y : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
f : X → Y
inst✝ : JacobsonSpace X
S : Set X
hS : IsLocallyClosed S
hf₁ : Continuous[inst✝², inst✝¹] f
hf₂ : IsClosedMap f
hfS : (f '' S).Finite
hS'' : S.Nonempty
hS' : IsIrreducible S
H₁ : IsIrreducible (S ∩ closedPoints X)
H₂ : f '' (S ∩ closedPoints X) ⊆ closedPoints Y
H₃ : (f '' (S ∩ closedPoints X)).Subsingleton
H₄ : IsClosed[inst✝¹] (f '' (S ∩ closedPoints X))
this : f '' closure[inst✝²] (S ∩ closedPoints X) ⊆ closure[inst✝¹] (f '' (S ∩ closedPoints X))
⊢ (f '' closure[inst✝²] S).Subsingleton

Tactic:
rw [JacobsonSpace.closure_inter_closedPoints_eq_closure hS, H₄.closure_eq] at this

Goal state after:
case inr
X : Type u_1
Y : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
f : X → Y
inst✝ : JacobsonSpace X
S : Set X
hS : IsLocallyClosed S
hf₁ : Continuous[inst✝², inst✝¹] f
hf₂ : IsClosedMap f
hfS : (f '' S).Finite
hS'' : S.Nonempty
hS' : IsIrreducible S
H₁ : IsIrreducible (S ∩ closedPoints X)
H₂ : f '' (S ∩ closedPoints X) ⊆ closedPoints Y
H₃ : (f '' (S ∩ closedPoints X)).Subsingleton
H₄ : IsClosed[inst✝¹] (f '' (S ∩ closedPoints X))
this : f '' closure[inst✝²] S ⊆ f '' (S ∩ closedPoints X)
⊢ (f '' closure[inst✝²] S).Subsingleton
Module: Mathlib.NumberTheory.RamificationInertia.Ramification

Goal state before:
pp: R : Type u
inst✝² : CommRing R
S : Type v
inst✝¹ : CommRing S
inst✝ : Algebra R S
p : Ideal R
P : Ideal S
n : ℕ
hn : ¬map f p ≤ P ^ n
⊢ p.ramificationIdx' P < n

Tactic:
exact ramificationIdx'_lt hn

Goal state after:
Module: Mathlib.NumberTheory.RamificationInertia.Ramification

Goal state before:
pp: R : Type u
inst✝⁵ : CommRing R
S : Type v
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : IsDedekindDomain S
inst✝¹ : IsDedekindDomain R
v : Ideal R
w : Ideal S
p : Ideal R
hv : Irreducible v
hp : Prime p
hvp : v ≠ p
inst✝ : w.LiesOver v
h : p ≤ comap f w
⊢ p = v

Tactic:
← under_def,

Goal state after:
R : Type u
inst✝⁵ : CommRing R
S : Type v
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : IsDedekindDomain S
inst✝¹ : IsDedekindDomain R
v : Ideal R
w : Ideal S
p : Ideal R
hv : Irreducible v
hp : Prime p
hvp : v ≠ p
inst✝ : w.LiesOver v
h : p ≤ under R w
⊢ p = v
Module: Mathlib.RingTheory.Unramified.Basic

Goal state before:
pp: case h₂
R : Type v
inst✝⁴ : CommRing R
A : Type u
inst✝³ : CommRing A
inst✝² : Algebra R A
B : Type w
inst✝¹ : CommRing B
inst✝ : FormallyUnramified R A
I : Ideal B
hI : IsNilpotent I
⊢ ∀ ⦃S : Type w⦄ [inst : CommRing S] (I J : Ideal S),
    I ≤ J →
      (∀ [inst_1 : Algebra R S], Function.Injective (Ideal.Quotient.mkₐ R I).comp) →
        (∀ [inst_1 : Algebra R (S ⧸ I)],
            Function.Injective (Ideal.Quotient.mkₐ R (Ideal.map (Ideal.Quotient.mk I) J)).comp) →
          ∀ [inst_1 : Algebra R S], Function.Injective (Ideal.Quotient.mkₐ R J).comp

Tactic:
intro B _ I J hIJ h₁ h₂ _ g₁ g₂ e

Goal state after:
case h₂
R : Type v
inst✝⁶ : CommRing R
A : Type u
inst✝⁵ : CommRing A
inst✝⁴ : Algebra R A
B✝ : Type w
inst✝³ : CommRing B✝
inst✝² : FormallyUnramified R A
I✝ : Ideal B✝
hI : IsNilpotent I✝
B : Type w
inst✝¹ : CommRing B
I J : Ideal B
hIJ : I ≤ J
h₁ : ∀ [inst : Algebra R B], Function.Injective (Ideal.Quotient.mkₐ R I).comp
h₂ : ∀ [inst : Algebra R (B ⧸ I)], Function.Injective (Ideal.Quotient.mkₐ R (Ideal.map (Ideal.Quotient.mk I) J)).comp
inst✝ : Algebra R B
g₁ g₂ : A →ₐ[R] B
e : (Ideal.Quotient.mkₐ R J).comp g₁ = (Ideal.Quotient.mkₐ R J).comp g₂
⊢ g₁ = g₂
Module: Mathlib.RingTheory.QuasiFinite.Basic

Goal state before:
pp: R : Type u_1
S : Type u_2
T : Type u_3
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : CommRing T
inst✝⁵ : Algebra R S
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
M : Submonoid S
inst✝¹ : IsLocalization M T
inst✝ : QuasiFinite R S
P : Ideal S
hP : P.IsPrime
⊢ Submodule.span S {t | ∃ m n, m ⊗ₜ[S] n = t} ≤ (↑S (Algebra.linearMap P.ResidueField (P.Fiber T))).range

Tactic:
Submodule.span_le

Goal state after:
R : Type u_1
S : Type u_2
T : Type u_3
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : CommRing T
inst✝⁵ : Algebra R S
inst✝⁴ : Algebra R T
inst✝³ : Algebra S T
inst✝² : IsScalarTower R S T
M : Submonoid S
inst✝¹ : IsLocalization M T
inst✝ : QuasiFinite R S
P : Ideal S
hP : P.IsPrime
⊢ {t | ∃ m n, m ⊗ₜ[S] n = t} ⊆ ↑(↑S (Algebra.linearMap P.ResidueField (P.Fiber T))).range