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

Goal state before:
pp: F : Type u_1
inst✝⁶ : Field F
E : Type u_2
inst✝⁵ : Field E
inst✝⁴ : Algebra F E
p : F[X]
hFE : FiniteDimensional F E
sp : Polynomial.IsSplittingField F E p
hp : p.Separable
K : Type u_3
inst✝³ : Field K
inst✝² : Algebra F K
inst✝¹ : Algebra K E
inst✝ : IsScalarTower F K E
x : E
hx : x ∈ p.aroots E
h : IsIntegral K x
h1 : p ≠ 0
h2 : minpoly K x ∣ Polynomial.map (algebraMap F K) p
key_equiv : (↥(IntermediateField.restrictScalars F K⟮x⟯) →ₐ[F] E) ≃ (f : K →ₐ[F] E) × (↥K⟮x⟯ →ₐ[K] E) := ⋯
this✝ : ∀ (f : K →ₐ[F] E), Finite (↥K⟮x⟯ →ₐ[K] E)
this : FiniteDimensional F K
⊢ ∀ x_1 ∈ Finset.univ, Nat.card (↥K⟮x⟯ →ₐ[K] E) = (minpoly K x).natDegree

Tactic:
intro f _

Goal state after:
F : Type u_1
inst✝⁶ : Field F
E : Type u_2
inst✝⁵ : Field E
inst✝⁴ : Algebra F E
p : F[X]
hFE : FiniteDimensional F E
sp : Polynomial.IsSplittingField F E p
hp : p.Separable
K : Type u_3
inst✝³ : Field K
inst✝² : Algebra F K
inst✝¹ : Algebra K E
inst✝ : IsScalarTower F K E
x : E
hx : x ∈ p.aroots E
h : IsIntegral K x
h1 : p ≠ 0
h2 : minpoly K x ∣ Polynomial.map (algebraMap F K) p
key_equiv : (↥(IntermediateField.restrictScalars F K⟮x⟯) →ₐ[F] E) ≃ (f : K →ₐ[F] E) × (↥K⟮x⟯ →ₐ[K] E) :=
  id algHomEquivSigma
this✝ : ∀ (f : K →ₐ[F] E), Finite (↥K⟮x⟯ →ₐ[K] E)
this : FiniteDimensional F K
f : K →ₐ[F] E
a✝ : f ∈ Finset.univ
⊢ Nat.card (↥K⟮x⟯ →ₐ[K] E) = (minpoly K x).natDegree
Module: Mathlib.FieldTheory.Galois.GaloisClosure

Goal state before:
pp: k : Type u_1
K : Type u_2
inst✝² : Field k
inst✝¹ : Field K
inst✝ : Algebra k K
α : Gal(K/k)
L : FiniteGaloisIntermediateField k K
⊢ α ∈ L.fixingSubgroup ↔ (AlgEquiv.restrictNormalHom ↥L.toIntermediateField) α = 1

Tactic:
simp [IntermediateField.fixingSubgroup, mem_fixingSubgroup_iff, AlgEquiv.ext_iff, Subtype.ext_iff,
    AlgEquiv.restrictNormalHom_apply]

Goal state after:
Module: Mathlib.FieldTheory.SeparableDegree

Goal state before:
pp: F : Type u_1
inst✝ : Field F
⊢ PerfectField F ↔ ∀ (f : F[X]), f.natSepDegree = 1 → f.Splits

Tactic:
by
  refine ⟨fun ⟨h⟩ f hf ↦ ?_, fun h ↦ ?_⟩
  · have hf0 : f ≠ 0 := by aesop
    obtain ⟨u, hu⟩ := UniqueFactorizationMonoid.factors_prod hf0
    rw [← hu]
    refine (Splits.multisetProd fun g hg ↦ ?_).mul u.isUnit.splits
    specialize h (UniqueFactorizationMonoid.irreducible_of_factor g hg)
    have key := natSepDegree_le_of_dvd g f (UniqueFactorizationMonoid.dvd_of_mem_factors hg) hf0
    rw [h.natSepDegree_eq_natDegree, hf] at key
    exact Splits.of_natDegree_le_one key
  obtain ⟨p, _⟩ := ExpChar.exists F
  have := PerfectRing.ofSurjective F p fun x ↦ by
    obtain ⟨y, hy⟩ := Splits.exists_eval_eq_zero
      (h _ (pow_one p ▸ natSepDegree_X_pow_char_pow_sub_C p 1 x))
      ((degree_X_pow_sub_C (expChar_pos F p) x).symm ▸ Nat.cast_pos.2 (expChar_pos F p)).ne'
    exact ⟨y, by rwa [eval_sub, eval_X_pow, eval_C, sub_eq_zero] at hy⟩
  exact PerfectRing.toPerfectField F p

Goal state after:
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
L : IntermediateField k K
inst✝ : IsGalois k K
x : K
hx : ∀ f ∈ L.fixingSubgroup, f x = x
mem : x ∈ (adjoin ↥L {x}).toIntermediateField
this : IntermediateField.fixedField ⊤ = ⊥
⊢ ∀ f ∈ ⊤, f ⟨x, mem⟩ = ⟨x, mem⟩

Tactic:
intro f _

Goal state after:
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
L : IntermediateField k K
inst✝ : IsGalois k K
x : K
hx : ∀ f ∈ L.fixingSubgroup, f x = x
mem : x ∈ (adjoin ↥L {x}).toIntermediateField
this : IntermediateField.fixedField ⊤ = ⊥
f : Gal(↥(adjoin ↥L {x}).toIntermediateField/↥L)
a✝ : f ∈ ⊤
⊢ f ⟨x, mem⟩ = ⟨x, mem⟩
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
⊢ eval x (minpolyDiv R x) = (aeval x) (derivative (minpoly R x))

Tactic:
rw [← eval_map_algebraMap, ← derivative_map, ← minpolyDiv_spec R x]

Goal state after:
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
⊢ eval x (minpolyDiv R x) = eval x (derivative (minpolyDiv R x * (X - C x)))
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
hj : j < i
⊢ j ∈ (fun x_1 ↦ x ^ x_1) ⁻¹' ↑(Submodule.span R (Set.range (minpolyDiv R x).coeff))

Tactic:
exact hi j hj (lt_trans hj hi')

Goal state after:
Module: Mathlib.FieldTheory.IsSepClosed

Goal state before:
pp: k : Type u
inst✝¹ : Field k
inst✝ : IsSepClosed k
n : ℕ
a b c : k
hn : ↑n = 0
hn' : 2 ≤ n
hb : b ≠ 0
f : k[X] := C a * X ^ n + C b * X + C c
⊢ ∃ x, a * x ^ n + b * x + c = 0

Tactic:
have hdeg : f.degree ≠ 0 := degree_ne_of_natDegree_ne (n := 0) <| by
    have : C 0 * X ^ n + C b * X = 0 * X ^ n + C b * X := by grind
    by_cases ha : a = 0
    · grind [zero_add]
    · grind [natDegree_add_eq_left_of_natDegree_lt]

Goal state after:
k : Type u
inst✝¹ : Field k
inst✝ : IsSepClosed k
n : ℕ
a b c : k
hn : ↑n = 0
hn' : 2 ≤ n
hb : b ≠ 0
f : k[X] := C a * X ^ n + C b * X + C c
hdeg : f.degree ≠ 0
⊢ ∃ x, a * x ^ n + b * x + c = 0
Module: Mathlib.FieldTheory.Galois.Infinite

Goal state before:
pp: case a
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
L : IntermediateField k K
inst✝ : IsGalois k K
h : L.fixingSubgroup.Normal
g : (x : K) → Subgroup Gal(↥(adjoin k {x}).toIntermediateField/k) := ⋯
f : ↥L → IntermediateField k K := ⋯
this✝ : ∀ (x : K), (g x).Normal
this : ∀ (l : ↥L), Normal k ↥(f l)
n : Normal k ↥(⨆ l, f l)
⊢ ⨆ l, f l ≤ L

pp: case a
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
L : IntermediateField k K
inst✝ : IsGalois k K
h : L.fixingSubgroup.Normal
g : (x : K) → Subgroup Gal(↥(adjoin k {x}).toIntermediateField/k) := ⋯
f : ↥L → IntermediateField k K := ⋯
this✝ : ∀ (x : K), (g x).Normal
this : ∀ (l : ↥L), Normal k ↥(f l)
n : Normal k ↥(⨆ l, f l)
⊢ L ≤ ⨆ l, f l

Tactic:
· apply iSup_le
        intro l
        simpa only [f, g, ← restrict_fixedField L.fixingSubgroup (adjoin k {l.1}),
          fixedField_fixingSubgroup L] using inf_le_left

Goal state after:
case a
k : Type u_1
K : Type u_2
inst✝³ : Field k
inst✝² : Field K
inst✝¹ : Algebra k K
L : IntermediateField k K
inst✝ : IsGalois k K
h : L.fixingSubgroup.Normal
g : (x : K) → Subgroup Gal(↥(adjoin k {x}).toIntermediateField/k) := ⋯
f : ↥L → IntermediateField k K := ⋯
this✝ : ∀ (x : K), (g x).Normal
this : ∀ (l : ↥L), Normal k ↥(f l)
n : Normal k ↥(⨆ l, f l)
⊢ L ≤ ⨆ l, f l
Module: Mathlib.FieldTheory.PurelyInseparable.Basic

Goal state before:
pp: case h
F : Type u
E : Type v
inst✝⁸ : Field F
inst✝⁷ : Field E
inst✝⁶ : Algebra F E
K : Type w
inst✝⁵ : Field K
inst✝⁴ : Algebra F K
R : Type u_1
A : Type u_2
inst✝³ : CommSemiring R
inst✝² : CommSemiring A
inst✝¹ : Algebra R A
p : ℕ
inst✝ : ExpChar A p
x y : A
n : ℕ
hx : x ^ p ^ n ∈ (algebraMap R A).rangeS
m : ℕ
hy : y ^ p ^ m ∈ (algebraMap R A).rangeS
⊢ (x + y) ^ p ^ (n + m) ∈ (algebraMap R A).rangeS

Tactic:
rw [add_pow_expChar_pow, pow_add, pow_mul, mul_comm (_ ^ n), pow_mul]

Goal state after:
case h
F : Type u
E : Type v
inst✝⁸ : Field F
inst✝⁷ : Field E
inst✝⁶ : Algebra F E
K : Type w
inst✝⁵ : Field K
inst✝⁴ : Algebra F K
R : Type u_1
A : Type u_2
inst✝³ : CommSemiring R
inst✝² : CommSemiring A
inst✝¹ : Algebra R A
p : ℕ
inst✝ : ExpChar A p
x y : A
n : ℕ
hx : x ^ p ^ n ∈ (algebraMap R A).rangeS
m : ℕ
hy : y ^ p ^ m ∈ (algebraMap R A).rangeS
⊢ (x ^ p ^ n) ^ p ^ m + (y ^ p ^ m) ^ p ^ n ∈ (algebraMap R A).rangeS
Module: Mathlib.Data.ZMod.ValMinAbs

Goal state before:
pp: case mpr.inr
n : ℕ
b : ZMod n
⊢ (-b).valMinAbs.natAbs = b.valMinAbs.natAbs

Tactic:
rw [natAbs_valMinAbs_neg]

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

Goal state before:
pp: K : Type u_1
inst✝² : CommRing K
inst✝¹ : NoZeroDivisors K
G : Subgroup Kˣ
inst✝ : Fintype ↥G
k : ℕ
k_pos : k ≠ 0
k_lt_card_G : k < Nat.card ↥G
a✝ : Nontrivial K
this : IsDomain K
a : ↥G
ha : a ^ k ≠ 1
h_multiset_map : Multiset.map (fun x ↦ ↑↑x ^ k) univ.val = Multiset.map (fun x ↦ ↑↑x ^ k * ↑↑a ^ k) univ.val
⊢ (Multiset.map (fun x ↦ ↑↑x ^ k) univ.val).sum = (Multiset.map (fun x ↦ ↑↑x ^ k * ↑↑a ^ k) univ.val).sum

Tactic:
rw [h_multiset_map]

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

Goal state before:
pp: case refine_1
G : Type u_1
inst✝¹⁰ : Group G
inst✝⁹ : Finite G
A : Type u_5
B : Type u_6
C : Type u_7
H : Subgroup G
inst✝⁸ : CommRing A
inst✝⁷ : CommRing B
inst✝⁶ : CommRing C
inst✝⁵ : IsDomain C
inst✝⁴ : Algebra A C
inst✝³ : FaithfulSMul A C
inst✝² : MulSemiringAction G C
hGAC : IsGaloisGroup G A C
inst✝¹ : Algebra B C
inst✝ : FaithfulSMul B C
hH : IsGaloisGroup (↥H) B C
this✝² : IsDomain B
this✝¹ : IsDomain A
K : Type u_5 := FractionRing A
L : Type u_7 := FractionRing C
this✝ : MulSemiringAction G L := IsFractionRing.mulSemiringAction G C L
this : IsGaloisGroup (↥H) (FractionRing B) L
g : G
⊢ (∀ (y : C), (∃ y_1, (algebraMap B C) y_1 = y) → g • y = y) →
    ∀ (y : L), (∃ y_1, (algebraMap (FractionRing B) L) y_1 = y) → g • y = y

pp: case refine_2
G : Type u_1
inst✝¹⁰ : Group G
inst✝⁹ : Finite G
A : Type u_5
B : Type u_6
C : Type u_7
H : Subgroup G
inst✝⁸ : CommRing A
inst✝⁷ : CommRing B
inst✝⁶ : CommRing C
inst✝⁵ : IsDomain C
inst✝⁴ : Algebra A C
inst✝³ : FaithfulSMul A C
inst✝² : MulSemiringAction G C
hGAC : IsGaloisGroup G A C
inst✝¹ : Algebra B C
inst✝ : FaithfulSMul B C
hH : IsGaloisGroup (↥H) B C
this✝² : IsDomain B
this✝¹ : IsDomain A
K : Type u_5 := FractionRing A
L : Type u_7 := FractionRing C
this✝ : MulSemiringAction G L := IsFractionRing.mulSemiringAction G C L
this : IsGaloisGroup (↥H) (FractionRing B) L
g : G
⊢ (∀ (y : L), (∃ y_1, (algebraMap (FractionRing B) L) y_1 = y) → g • y = y) →
    ∀ (y : C), (∃ y_1, (algebraMap B C) y_1 = y) → g • y = y

Tactic:
· rintro h _ ⟨x, rfl⟩
    have {x} : g • (algebraMap B L) x = (algebraMap B L) x := by
      rw [IsScalarTower.algebraMap_apply B C L, ← algebraMap.smul', h _ ⟨x, rfl⟩]
    obtain ⟨a, b, _, rfl⟩ := IsFractionRing.div_surjective B x
    simp only [map_div₀, ← IsScalarTower.algebraMap_apply, smul_div₀', this]

Goal state after:
case refine_2
G : Type u_1
inst✝¹⁰ : Group G
inst✝⁹ : Finite G
A : Type u_5
B : Type u_6
C : Type u_7
H : Subgroup G
inst✝⁸ : CommRing A
inst✝⁷ : CommRing B
inst✝⁶ : CommRing C
inst✝⁵ : IsDomain C
inst✝⁴ : Algebra A C
inst✝³ : FaithfulSMul A C
inst✝² : MulSemiringAction G C
hGAC : IsGaloisGroup G A C
inst✝¹ : Algebra B C
inst✝ : FaithfulSMul B C
hH : IsGaloisGroup (↥H) B C
this✝² : IsDomain B
this✝¹ : IsDomain A
K : Type u_5 := FractionRing A
L : Type u_7 := FractionRing C
this✝ : MulSemiringAction G L := IsFractionRing.mulSemiringAction G C L
this : IsGaloisGroup (↥H) (FractionRing B) L
g : G
⊢ (∀ (y : L), (∃ y_1, (algebraMap (FractionRing B) L) y_1 = y) → g • y = y) →
    ∀ (y : C), (∃ y_1, (algebraMap B C) y_1 = y) → g • y = y
Module: Mathlib.Data.Int.Associated

Goal state before:
pp: a b : ℤ
⊢ a.natAbs = b.natAbs ↔ Associated a b

Tactic:
refine Int.natAbs_eq_natAbs_iff.trans ?_
  constructor
  · rintro (rfl | rfl)
    · rfl
    · exact ⟨-1, by simp⟩
  · rintro ⟨u, rfl⟩
    obtain rfl | rfl := Int.units_eq_one_or u
    · exact Or.inl (by simp)
    · exact Or.inr (by simp)

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
x : ↥F
h : ∀ (g : ↥(Subgroup.map (QuotientGroup.mk' N) H)), g • x = x
a : ↥E
ha : (algebraMap (↥E) L) a = (algebraMap (↥F) L) x
⊢ (algebraMap (↥F) L) ((algebraMap ↥E ↥F) a) = (algebraMap (↥F) L) x

Tactic:
by rw [← IsScalarTower.algebraMap_apply, ha]

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

Goal state before:
pp: K : Type u_1
inst✝¹ : Field K
inst✝ : Fintype K
⊢ (X ^ q - X).roots = univ.val

Tactic:
have aux : (X ^ q - X : K[X]) ≠ 0 := X_pow_card_sub_X_ne_zero K Fintype.one_lt_card
    have : (roots (X ^ q - X : K[X])).toFinset = Finset.univ := by
      rw [eq_univ_iff_forall]
      intro x
      rw [Multiset.mem_toFinset, mem_roots aux, IsRoot.def, eval_sub, eval_pow, eval_X,
        sub_eq_zero, pow_card]
    rw [← this, Multiset.toFinset_val, eq_comm, Multiset.dedup_eq_self]
    apply nodup_roots
    rw [separable_def]
    convert! isCoprime_one_right.neg_right (R := K[X]) using 1
    rw [derivative_sub, derivative_X, derivative_X_pow, Nat.cast_card_eq_zero K, C_0,
      zero_mul, zero_sub]

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

Goal state before:
pp: case intro
A : Type u_1
B : Type u_2
inst✝¹⁸ : CommRing A
inst✝¹⁷ : CommRing B
inst✝¹⁶ : Algebra A B
G : Type u_3
inst✝¹⁵ : Group G
inst✝¹⁴ : Finite G
inst✝¹³ : MulSemiringAction G B
inst✝¹² : SMulCommClass G A B
P : Ideal A
Q : Ideal B
inst✝¹¹ : Q.IsPrime
inst✝¹⁰ : Q.LiesOver P
K : Type u_4
L : Type u_5
inst✝⁹ : Field K
inst✝⁸ : Field L
inst✝⁷ : Algebra (A ⧸ P) K
inst✝⁶ : Algebra (B ⧸ Q) L
inst✝⁵ : Algebra (A ⧸ P) L
inst✝⁴ : IsScalarTower (A ⧸ P) (B ⧸ Q) L
inst✝³ : Algebra K L
inst✝² : IsScalarTower (A ⧸ P) K L
inst✝¹ : Algebra.IsInvariant A B G
inst✝ : Module.IsTorsionFree (B ⧸ Q) L
f : Gal(L/K)
val✝ : Fintype G
b₀ : B
hx :
  ∀ (g : ↥(MulAction.stabilizer G Q)),
    ((Ideal.Quotient.stabilizerHom Q P G) g) ((Ideal.Quotient.mk Q) b₀) = (Ideal.Quotient.mk Q) b₀
b : B
M : A[X]
a : A
ha1 : ∀ (g : G), g • (algebraMap A B) a = (algebraMap A B) a
ha2 : (algebraMap A B) a ∉ Q
hb :
  ∀ (g : G), (algebraMap B (B ⧸ Q)) (g • b) = (algebraMap B (B ⧸ Q)) (if g • Q = Q then (algebraMap A B) a * b₀ else 0)
key₀ :
  ∀ (g : G),
    map (algebraMap B (B ⧸ Q)) (X - C (g • b)) =
      if g • Q = Q then X - C ((algebraMap B (B ⧸ Q)) ((algebraMap A B) a * b₀)) else X
key :
  (algebraMap K L) ((algebraMap (A ⧸ P) K) ((algebraMap A (A ⧸ P)) a)) *
      f ((algebraMap (B ⧸ Q) L) ((algebraMap B (B ⧸ Q)) b₀)) =
    (algebraMap K L) ((algebraMap (A ⧸ P) K) ((algebraMap A (A ⧸ P)) a)) *
      (algebraMap (B ⧸ Q) L) ((algebraMap B (B ⧸ Q)) b₀)
⊢ (algebraMap K L) ((algebraMap (A ⧸ P) K) ((algebraMap A (A ⧸ P)) a)) ≠ 0

Tactic:
rwa [← algebraMap_apply, algebraMap_apply (A ⧸ P) (B ⧸ Q) L,
      ← algebraMap_apply A (A ⧸ P) (B ⧸ Q), algebraMap_apply A B (B ⧸ Q),
      Ne, algebraMap_eq_zero_iff, Ideal.Quotient.algebraMap_eq, Ideal.Quotient.eq_zero_iff_mem]

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
g : Fˣ
hg : ∀ (x : Fˣ), x ∈ Subgroup.zpowers g
n : ℕ
hodd : 2 * (Nat.card F / 2) = Nat.card F - 1
h : g ^ (n * (Nat.card F / 2)) = 1
⊢ orderOf g ∣ n * (Nat.card F / 2)

Tactic:
apply orderOf_dvd_of_pow_eq_one h

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

Goal state before:
pp: S : Type u_1
inst✝ : CommRing S
I J : Ideal S
coprime : IsCoprime I J
⊢ cardQuot (I * J) = cardQuot I * cardQuot J

Tactic:
by
  rw [cardQuot_apply, cardQuot_apply, cardQuot_apply,
    Nat.card_congr (Ideal.quotientMulEquivQuotientProd I J coprime).toEquiv,
    Nat.card_prod]

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

Goal state before:
pp: R : Type u_1
S : Type u_2
T : Type u_3
inst✝¹⁰ : CommRing R
inst✝⁹ : CommRing S
inst✝⁸ : CommRing T
inst✝⁷ : Algebra R S
inst✝⁶ : Algebra S T
inst✝⁵ : Algebra R T
inst✝⁴ : IsScalarTower R S T
p : Ideal R
P : Ideal S
I : Ideal T
inst✝³ : p.IsMaximal
inst✝² : P.IsMaximal
inst✝¹ : P.LiesOver p
inst✝ : I.LiesOver P
h₁ : p = under R P
h₂ : P = under S I
h₃ : p = under R I
this✝¹ : Algebra (R ⧸ p) (S ⧸ P) := Quotient.algebraQuotientOfLEComap ⋯
this✝ : Algebra (S ⧸ P) (T ⧸ I) := Quotient.algebraQuotientOfLEComap ⋯
this : Algebra (R ⧸ p) (T ⧸ I) := Quotient.algebraQuotientOfLEComap ⋯
⊢ ∀ (x : R ⧸ p), (algebraMap (R ⧸ p) (T ⧸ I)) x = (algebraMap (S ⧸ P) (T ⧸ I)) ((algebraMap (R ⧸ p) (S ⧸ P)) x)

Tactic:
rintro ⟨x⟩; exact congr_arg _ (IsScalarTower.algebraMap_apply R S T x)

Goal state after:
Module: Mathlib.RingTheory.Artinian.Ring

Goal state before:
pp: R : Type u_1
inst✝¹ : CommRing R
inst✝ : IsArtinianRing R
I : Ideal R
⊢ I.jacobson = I.radical

Tactic:
simp_rw [Ideal.jacobson, Ideal.radical_eq_sInf, IsArtinianRing.isPrime_iff_isMaximal]

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

Goal state before:
pp: case IJ
S : Type u_1
inst✝² : CommRing S
inst✝¹ : IsDedekindDomain S
inst✝ : Free ℤ S
I : Ideal S
hI : Nat.Prime (absNorm I)
this : (span {↑(absNorm I)}).IsPrime
⊢ span {↑(absNorm I)} ≤ comap (algebraMap ℤ S) I

Tactic:
span_singleton_le_iff_mem,

Goal state after:
case IJ
S : Type u_1
inst✝² : CommRing S
inst✝¹ : IsDedekindDomain S
inst✝ : Free ℤ S
I : Ideal S
hI : Nat.Prime (absNorm I)
this : (span {↑(absNorm I)}).IsPrime
⊢ ↑(absNorm I) ∈ comap (algebraMap ℤ S) I
Module: Mathlib.RingTheory.Ideal.Norm.AbsNorm

Goal state before:
pp: S : Type u_1
inst✝⁴ : CommRing S
inst✝³ : IsDedekindDomain S
inst✝² : Free ℤ S
inst✝¹ : Module.Finite ℤ S
P : Ideal S
inst✝ : P.IsMaximal
this✝ : IsAddTorsionFree S
this : CharZero S
⊢ ∃ p n, 0 < n ∧ ↑p ∈ P ∧ Nat.Prime p ∧ absNorm P = p ^ n

Tactic:
have : Finite (S ⧸ P) := Submodule.finiteQuotientOfFreeOfRankEq (P.restrictScalars ℤ)
    (Ideal.finrank_eq_finrank (Module.Free.chooseBasis _ _) _
      (Ideal.IsMaximal.ne_bot_of_isIntegral_int P))

Goal state after:
S : Type u_1
inst✝⁴ : CommRing S
inst✝³ : IsDedekindDomain S
inst✝² : Free ℤ S
inst✝¹ : Module.Finite ℤ S
P : Ideal S
inst✝ : P.IsMaximal
this✝¹ : IsAddTorsionFree S
this✝ : CharZero S
this : Finite (S ⧸ P)
⊢ ∃ p n, 0 < n ∧ ↑p ∈ P ∧ Nat.Prime p ∧ absNorm P = p ^ n
Module: Mathlib.RingTheory.Ideal.Norm.AbsNorm

Goal state before:
pp: case h₂
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 : Ideal S
hI' : IsUnit I
hI : p ∣ ↑(absNorm I)
⊢ ∃ P, P.IsMaximal ∧ under ℤ P = span {p} ∧ P ∣ I

Tactic:
obtain rfl : I = ⊤ := by simpa using hI'
    cases hp.not_dvd_one (by simpa using hI)

Goal state after:
Module: Mathlib.Topology.JacobsonSpace

Goal state before:
pp: X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
hf : Function.Injective f
hf' : Continuous[inst✝¹, inst✝] f
x : X
hx : x ∈ f ⁻¹' closedPoints Y
⊢ IsClosed[inst✝¹] {x}

Tactic:
convert! continuous_iff_isClosed.mp hf' _ hx

Goal state after:
X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
hf : Function.Injective f
hf' : Continuous[inst✝¹, inst✝] f
x : X
hx : x ∈ f ⁻¹' closedPoints Y
⊢ {x} = f ⁻¹' {f x}
Module: Mathlib.RingTheory.Unramified.Basic

Goal state before:
pp: R : Type u_1
inst✝⁷ : CommRing R
A : Type u_2
B : Type u_3
inst✝⁶ : CommRing A
inst✝⁵ : Algebra R A
inst✝⁴ : CommRing B
inst✝³ : Algebra R B
inst✝² : FormallyUnramified R A
e : A ≃ₐ[R] B
C : Type u_3
inst✝¹ : CommRing C
inst✝ : Algebra R C
I : Ideal C
hI : I ^ 2 = ⊥
f₁ f₂ : B →ₐ[R] C
e' : (Ideal.Quotient.mkₐ R I).comp f₁ = (Ideal.Quotient.mkₐ R I).comp f₂
⊢ (f₁.comp ↑e).comp ↑e.symm = f₂.comp ((↑e).comp ↑e.symm)

Tactic:
← AlgHom.comp_assoc

Goal state after:
R : Type u_1
inst✝⁷ : CommRing R
A : Type u_2
B : Type u_3
inst✝⁶ : CommRing A
inst✝⁵ : Algebra R A
inst✝⁴ : CommRing B
inst✝³ : Algebra R B
inst✝² : FormallyUnramified R A
e : A ≃ₐ[R] B
C : Type u_3
inst✝¹ : CommRing C
inst✝ : Algebra R C
I : Ideal C
hI : I ^ 2 = ⊥
f₁ f₂ : B →ₐ[R] C
e' : (Ideal.Quotient.mkₐ R I).comp f₁ = (Ideal.Quotient.mkₐ R I).comp f₂
⊢ (f₁.comp ↑e).comp ↑e.symm = (f₂.comp ↑e).comp ↑e.symm
Module: Mathlib.RingTheory.QuasiFinite.Basic

Goal state before:
pp: case neg
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
inst✝ : QuasiFinite R S
I : Ideal R
h : ¬I.IsPrime
⊢ (I.primesOver S).Finite

Tactic:
convert! Set.finite_empty
    by_contra!
    obtain ⟨J, h₁, ⟨rfl⟩⟩ := this
    exact h inferInstance

Goal state after:
Module: Mathlib.RingTheory.Unramified.Finite

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
I : Type u_4
inst✝ : DecidableEq I
b : Basis I R S
f : I →₀ S
x : S
a : I → I →₀ R
ha : a = fun i ↦ b.repr (b i * x)
⊢ (1 ⊗ₜ[R] x * f.sum fun i y ↦ y ⊗ₜ[R] b i) =
    ∑ k ∈ f.support.biUnion fun i ↦ (a i).support,
      (b.repr (f.sum fun i y ↦ (a i) k • y)).sum fun j c ↦ c • b j ⊗ₜ[R] b k

Tactic:
Finsupp.sum,

Goal state after:
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
I : Type u_4
inst✝ : DecidableEq I
b : Basis I R S
f : I →₀ S
x : S
a : I → I →₀ R
ha : a = fun i ↦ b.repr (b i * x)
⊢ 1 ⊗ₜ[R] x * ∑ a ∈ f.support, f a ⊗ₜ[R] b a =
    ∑ k ∈ f.support.biUnion fun i ↦ (a i).support,
      (b.repr (f.sum fun i y ↦ (a i) k • y)).sum fun j c ↦ c • b j ⊗ₜ[R] b k
Module: Mathlib.RingTheory.Unramified.Finite

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
I : Type u_4
inst✝ : DecidableEq I
b : Basis I R S
f : I →₀ S
x : S
a : I → I →₀ R := fun i ↦ b.repr (b i * x)
h₁ :
  ∀ (k : I),
    ((f.sum fun i y ↦ (b.repr (b i * x)) k • b.repr y).sum fun j z ↦ z • b j ⊗ₜ[R] b k) =
      f.sum fun i y ↦ (b.repr y).sum fun j z ↦ (b.repr (b i * x)) k • z • b j ⊗ₜ[R] b k
h₂ : ∀ (x : S), ∑ a ∈ (b.repr x).support, (b.repr x) a • b a = x
⊢ ∑ i ∈ f.support, ∑ x ∈ (a i).support, ((a i) x • f i) ⊗ₜ[R] b x =
    ∑ x_1 ∈ f.support.biUnion fun i ↦ (b.repr (b i * x)).support,
      f.sum fun i y ↦ (b.repr y).sum fun j z ↦ (b.repr (b i * x)) x_1 • z • b j ⊗ₜ[R] b x_1

Tactic:
Finsupp.sum,

Goal state after:
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
I : Type u_4
inst✝ : DecidableEq I
b : Basis I R S
f : I →₀ S
x : S
a : I → I →₀ R := fun i ↦ b.repr (b i * x)
h₁ :
  ∀ (k : I),
    ((f.sum fun i y ↦ (b.repr (b i * x)) k • b.repr y).sum fun j z ↦ z • b j ⊗ₜ[R] b k) =
      f.sum fun i y ↦ (b.repr y).sum fun j z ↦ (b.repr (b i * x)) k • z • b j ⊗ₜ[R] b k
h₂ : ∀ (x : S), ∑ a ∈ (b.repr x).support, (b.repr x) a • b a = x
⊢ ∑ i ∈ f.support, ∑ x ∈ (a i).support, ((a i) x • f i) ⊗ₜ[R] b x =
    ∑ x_1 ∈ f.support.biUnion fun i ↦ (b.repr (b i * x)).support,
      ∑ a ∈ f.support, ∑ x_2 ∈ (b.repr (f a)).support, (b.repr (b a * x)) x_1 • (b.repr (f a)) x_2 • b x_2 ⊗ₜ[R] b x_1