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

Goal state before:
pp: F : Type u_1
E : Type u_2
inst✝³ : Field F
inst✝² : Field E
inst✝¹ : Algebra F E
K L : IntermediateField F E
inst✝ : Normal F ↥K
h : K ⊔ L = ⊤
φ : Gal(E/↥L)
hφ : (restrictRestrictAlgEquivMapHom F (↥K) (↥L) E) φ = 1
⊢ (MulSemiringAction.toAlgAut Gal(E/↥L) F E) φ = 1

Tactic:
rw [← Subgroup.mem_bot, ← fixingSubgroup_top, ← h, fixingSubgroup_sup]

Goal state after:
F : Type u_1
E : Type u_2
inst✝³ : Field F
inst✝² : Field E
inst✝¹ : Algebra F E
K L : IntermediateField F E
inst✝ : Normal F ↥K
h : K ⊔ L = ⊤
φ : Gal(E/↥L)
hφ : (restrictRestrictAlgEquivMapHom F (↥K) (↥L) E) φ = 1
⊢ (MulSemiringAction.toAlgAut Gal(E/↥L) F E) φ ∈ K.fixingSubgroup ⊓ L.fixingSubgroup
Module: Mathlib.FieldTheory.Galois.Basic

Goal state before:
pp: case inr
F : Type u_1
E' : Type u_3
inst✝³ : Field F
inst✝² : Field E'
inst✝¹ : Algebra F E'
L : IntermediateField F E'
inst✝ : IsGalois F E'
this : ∀ (L : IntermediateField F E'), FiniteDimensional F ↥L → finrank F ↥L = L.fixingSubgroup.index
hnfd : ¬FiniteDimensional F ↥L
h : L.fixingSubgroup.FiniteIndex
L' : IntermediateField F ↥L
hL' : L.fixingSubgroup.index < finrank F ↥L'
i : ↥L' ≃ₗ[F] ↥(lift L') := ↑(liftAlgEquiv L')
hfd : FiniteDimensional F ↥(lift L')
⊢ False

Tactic:
i.finrank_eq,

Goal state after:
case inr
F : Type u_1
E' : Type u_3
inst✝³ : Field F
inst✝² : Field E'
inst✝¹ : Algebra F E'
L : IntermediateField F E'
inst✝ : IsGalois F E'
this : ∀ (L : IntermediateField F E'), FiniteDimensional F ↥L → finrank F ↥L = L.fixingSubgroup.index
hnfd : ¬FiniteDimensional F ↥L
h : L.fixingSubgroup.FiniteIndex
L' : IntermediateField F ↥L
hL' : L.fixingSubgroup.index < finrank F ↥(lift L')
i : ↥L' ≃ₗ[F] ↥(lift L') := ↑(liftAlgEquiv L')
hfd : FiniteDimensional F ↥(lift L')
⊢ False
Module: Mathlib.FieldTheory.Galois.Infinite

Goal state before:
pp: case h.left
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
σ : Gal(K/k)
h : σ ∈ (↑L.fixingSubgroup)ᶜ
y : K
yL : y ∈ ↑L
ne : y ∉ fun a ↦ σ • a = a
f : Gal(K/k)
hf : f ∈ σ • ↑(adjoin k {y}).fixingSubgroup
⊢ f ∈ (↑L.fixingSubgroup)ᶜ

Tactic:
rcases (Set.mem_smul_set.mp hf) with ⟨g, hg, eq⟩

Goal state after:
case h.left
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
σ : Gal(K/k)
h : σ ∈ (↑L.fixingSubgroup)ᶜ
y : K
yL : y ∈ ↑L
ne : y ∉ fun a ↦ σ • a = a
f : Gal(K/k)
hf : f ∈ σ • ↑(adjoin k {y}).fixingSubgroup
g : Gal(K/k)
hg : g ∈ ↑(adjoin k {y}).fixingSubgroup
eq : σ • g = f
⊢ f ∈ (↑L.fixingSubgroup)ᶜ
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 : R[X]
h : p.Monic
hp : Irreducible p
a b : K[X]
H : Polynomial.map (algebraMap R K) p = a * b
hₐ : ¬IsUnit a
a' : R[X]
ha : Polynomial.map (algebraMap R K) a' * C a.leadingCoeff = a
b' : R[X]
hb : Polynomial.map (algebraMap R K) b' * C b.leadingCoeff = b
⊢ (a * b).leadingCoeff = 1

Tactic:
← H,

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 : R[X]
h : p.Monic
hp : Irreducible p
a b : K[X]
H : Polynomial.map (algebraMap R K) p = a * b
hₐ : ¬IsUnit a
a' : R[X]
ha : Polynomial.map (algebraMap R K) a' * C a.leadingCoeff = a
b' : R[X]
hb : Polynomial.map (algebraMap R K) b' * C b.leadingCoeff = b
⊢ (Polynomial.map (algebraMap R K) p).leadingCoeff = 1
Module: Mathlib.FieldTheory.Minpoly.IsIntegrallyClosed

Goal state before:
pp: case refine_1
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
s : S
p : R[X]
hp : (Polynomial.aeval s) p = 0
h₀ : p ≠ 0
pmin : ∀ (q : R[X]), q.Monic → (Polynomial.aeval s) q = 0 → p.degree ≤ q.degree
x✝ : C p.leadingCoeff ∣ p
q : R[X]
hMul : p = C p.leadingCoeff * q
⊢ q.Monic

pp: case refine_2
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
s : S
p : R[X]
hp : (Polynomial.aeval s) p = 0
h₀ : p ≠ 0
pmin : ∀ (q : R[X]), q.Monic → (Polynomial.aeval s) q = 0 → p.degree ≤ q.degree
x✝ : C p.leadingCoeff ∣ p
q : R[X]
hMul : p = C p.leadingCoeff * q
⊢ (Polynomial.aeval s) q = 0

pp: case refine_3
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
s : S
p : R[X]
hp : (Polynomial.aeval s) p = 0
h₀ : p ≠ 0
pmin : ∀ (q : R[X]), q.Monic → (Polynomial.aeval s) q = 0 → p.degree ≤ q.degree
x✝ : C p.leadingCoeff ∣ p
q : R[X]
hMul : p = C p.leadingCoeff * q
⊢ ∀ (Q : R[X]), Q.Monic → (Polynomial.aeval s) Q = 0 → q.degree ≤ Q.degree

Tactic:
· have := hMul ▸ leadingCoeff_mul .. |>.symm
      simp only [leadingCoeff_C, ne_eq, leadingCoeff_eq_zero, h₀, not_false_eq_true, mul_eq_left₀]
        at this
      exact this

Goal state after:
case refine_2
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
s : S
p : R[X]
hp : (Polynomial.aeval s) p = 0
h₀ : p ≠ 0
pmin : ∀ (q : R[X]), q.Monic → (Polynomial.aeval s) q = 0 → p.degree ≤ q.degree
x✝ : C p.leadingCoeff ∣ p
q : R[X]
hMul : p = C p.leadingCoeff * q
⊢ (Polynomial.aeval s) q = 0

case refine_3
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
s : S
p : R[X]
hp : (Polynomial.aeval s) p = 0
h₀ : p ≠ 0
pmin : ∀ (q : R[X]), q.Monic → (Polynomial.aeval s) q = 0 → p.degree ≤ q.degree
x✝ : C p.leadingCoeff ∣ p
q : R[X]
hMul : p = C p.leadingCoeff * q
⊢ ∀ (Q : R[X]), Q.Monic → (Polynomial.aeval s) Q = 0 → q.degree ≤ Q.degree
Module: Mathlib.FieldTheory.Minpoly.MinpolyDiv

Goal state before:
pp: case succ
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
i : ℕ
IH :
  i ≤ (minpolyDiv R x).natDegree →
    (minpolyDiv R x).coeff ((minpolyDiv R x).natDegree - i) - x ^ i ∈
      Submodule.span R ((fun x_1 ↦ x ^ x_1) '' Set.Iio i)
hi : i + 1 ≤ (minpolyDiv R x).natDegree
⊢ (minpolyDiv R x).coeff ((minpolyDiv R x).natDegree - (i + 1)) - x ^ (i + 1) ∈
    Submodule.span R ((fun x_1 ↦ x ^ x_1) '' Set.Iio (i + 1))

Tactic:
rw [coeff_minpolyDiv, add_sub_assoc, pow_succ, ← sub_mul, Algebra.algebraMap_eq_smul_one]
    refine add_mem ?_ ?_
    · apply Submodule.smul_mem
      apply Submodule.subset_span
      exact ⟨0, Nat.zero_lt_succ _, pow_zero _⟩
    · rw [← tsub_tsub, tsub_add_cancel_of_le (le_tsub_of_add_le_left (b := 1) hi)]
      apply SetLike.le_def.mp ?_
        (Submodule.mul_mem_mul (IH ((Nat.le_succ _).trans hi))
          (Submodule.mem_span_singleton_self x))
      rw [Submodule.span_mul_span, Set.mul_singleton, Set.image_image]
      apply Submodule.span_mono
      rintro _ ⟨j, hj, rfl⟩
      rw [Set.mem_Iio] at hj
      exact ⟨j + 1, Nat.add_lt_of_lt_sub hj, pow_succ x j⟩

Goal state after:
Module: Mathlib.RingTheory.Polynomial.GaussLemma

Goal state before:
pp: R : Type u_1
inst✝⁵ : CommRing R
K : Type u_2
inst✝⁴ : Field K
inst✝³ : Algebra R K
inst✝² : IsFractionRing R K
inst✝¹ : IsDomain R
inst✝ : NormalizedGCDMonoid R
p : K[X]
h0 : p ≠ 0
h : IsUnit (integerNormalization R⁰ p).primPart
u : Rˣ
hu : C ↑u = (integerNormalization R⁰ p).primPart
c : R
c0 : c ∈ R⁰
hc : map (algebraMap R K) (integerNormalization R⁰ p) = c • p
⊢ IsUnit p

Tactic:
rw [Algebra.smul_def, algebraMap_apply] at hc

Goal state after:
R : Type u_1
inst✝⁵ : CommRing R
K : Type u_2
inst✝⁴ : Field K
inst✝³ : Algebra R K
inst✝² : IsFractionRing R K
inst✝¹ : IsDomain R
inst✝ : NormalizedGCDMonoid R
p : K[X]
h0 : p ≠ 0
h : IsUnit (integerNormalization R⁰ p).primPart
u : Rˣ
hu : C ↑u = (integerNormalization R⁰ p).primPart
c : R
c0 : c ∈ R⁰
hc : map (algebraMap R K) (integerNormalization R⁰ p) = C ((algebraMap R K) c) * p
⊢ IsUnit p
Module: Mathlib.FieldTheory.IsSepClosed

Goal state before:
pp: k : Type u
inst✝¹ : Field k
inst✝ : IsSepClosed k
p : k[X]
hsep : p.Separable
⊢ p.roots = 0 ↔ p = C (p.coeff 0)

Tactic:
refine ⟨fun h => ?_, fun hp => by rw [hp, roots_C]⟩

Goal state after:
k : Type u
inst✝¹ : Field k
inst✝ : IsSepClosed k
p : k[X]
hsep : p.Separable
h : p.roots = 0
⊢ p = C (p.coeff 0)
Module: Mathlib.FieldTheory.Minpoly.MinpolyDiv

Goal state before:
pp: case hcard.refine_1
K : Type u_2
L : Type u_3
inst✝⁷ : Field K
inst✝⁶ : Field L
inst✝⁵ : Algebra K L
E : Type u_1
inst✝⁴ : Field E
inst✝³ : Algebra K E
inst✝² : IsAlgClosed E
inst✝¹ : FiniteDimensional K L
inst✝ : Algebra.IsSeparable K L
x : L
hxL : K[x] = ⊤
r : ℕ
hr : r < finrank K L
this : Function.Injective fun σ ↦ σ x
⊢ Finset.fold max 0 (natDegree ∘ fun σ ↦ map (↑σ) ((x ^ r / (aeval x) (derivative (minpoly K x))) • minpolyDiv K x))
      Finset.univ <
    Fintype.card (L →ₐ[K] E)

Tactic:
simp only [Polynomial.map_smul,
        map_div₀, map_pow, RingHom.coe_coe, Function.comp_apply,
        Finset.mem_univ, forall_true_left, Finset.fold_max_lt, AlgHom.card]
      refine ⟨finrank_pos, ?_⟩
      intro σ
      exact ((Polynomial.natDegree_smul_le _ _).trans natDegree_map_le).trans_lt
        ((natDegree_minpolyDiv_lt (Algebra.IsIntegral.isIntegral x)).trans_le
          (minpoly.natDegree_le _))

Goal state after:
Module: Mathlib.FieldTheory.IsSepClosed

Goal state before:
pp: k : Type u
inst✝⁴ : Field k
K : Type v
inst✝³ : Field K
inst✝² : IsSepClosed k
inst✝¹ : Algebra k K
L : IntermediateField k K
inst✝ : Algebra.IsSeparable k ↥L
x : K
hx : x ∈ L
⊢ x ∈ ⊥

Tactic:
by
  obtain ⟨y, hy⟩ := IsSepClosed.algebraMap_surjective k L ⟨x, hx⟩
  exact ⟨y, congr_arg (algebraMap L K) hy⟩

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

Goal state before:
pp: F✝ : Type u
E✝ : Type v
inst✝¹¹ : Field F✝
inst✝¹⁰ : Field E✝
inst✝⁹ : Algebra F✝ E✝
q✝ : ℕ
inst✝⁸ : ExpChar F✝ q✝
inst✝⁷ : IsPurelyInseparable F✝ E✝
inst✝⁶ : FiniteDimensional F✝ E✝
E : Type v
inst✝⁵ : Field E
q d : ℕ
IH :
  ∀ m < d,
    ∀ (F : Type v) [inst : Field F] [inst_1 : Algebra F E] [ExpChar F q] [IsPurelyInseparable F E]
      [FiniteDimensional F E], finrank F E = m → ∃ n, m = q ^ n
F : Type v
inst✝⁴ : Field F
inst✝³ : Algebra F E
inst✝² : ExpChar F q
inst✝¹ : IsPurelyInseparable F E
inst✝ : FiniteDimensional F E
hd : finrank F E = d
h : ¬⊥ = ⊤
x : E
hx : x ∉ ⊥
m : ℕ
y : F
e : minpoly F x = X ^ q ^ m - C y
this : finrank F ↥F⟮x⟯ = q ^ m
⊢ finrank (↥F⟮x⟯) E < finrank F ↥F⟮x⟯ * finrank (↥F⟮x⟯) E

Tactic:
Nat.lt_mul_iff_one_lt_left finrank_pos,

Goal state after:
F✝ : Type u
E✝ : Type v
inst✝¹¹ : Field F✝
inst✝¹⁰ : Field E✝
inst✝⁹ : Algebra F✝ E✝
q✝ : ℕ
inst✝⁸ : ExpChar F✝ q✝
inst✝⁷ : IsPurelyInseparable F✝ E✝
inst✝⁶ : FiniteDimensional F✝ E✝
E : Type v
inst✝⁵ : Field E
q d : ℕ
IH :
  ∀ m < d,
    ∀ (F : Type v) [inst : Field F] [inst_1 : Algebra F E] [ExpChar F q] [IsPurelyInseparable F E]
      [FiniteDimensional F E], finrank F E = m → ∃ n, m = q ^ n
F : Type v
inst✝⁴ : Field F
inst✝³ : Algebra F E
inst✝² : ExpChar F q
inst✝¹ : IsPurelyInseparable F E
inst✝ : FiniteDimensional F E
hd : finrank F E = d
h : ¬⊥ = ⊤
x : E
hx : x ∉ ⊥
m : ℕ
y : F
e : minpoly F x = X ^ q ^ m - C y
this : finrank F ↥F⟮x⟯ = q ^ m
⊢ 1 < finrank F ↥F⟮x⟯
Module: Mathlib.NumberTheory.NumberField.Basic

Goal state before:
pp: K✝ : Type u_1
L✝ : Type u_2
inst✝³ : Field K✝
inst✝² : Field L✝
K : Type u_3
L : Type u_4
inst✝¹ : Field K
inst✝ : Field L
f : K →+* L
⊢ ↑⟨f ↑1, ⋯⟩ = ↑1

Tactic:
simp only [map_mk, map_one]

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

Goal state before:
pp: case h
G : Type u_1
inst✝⁸ : Group G
A : Type u_2
B : Type u_3
inst✝⁷ : CommRing A
inst✝⁶ : CommRing B
inst✝⁵ : IsDomain B
inst✝⁴ : Algebra A B
inst✝³ : FaithfulSMul A B
inst✝² : MulSemiringAction G B
inst✝¹ : IsGaloisGroup G A B
inst✝ : Finite G
this✝ : IsDomain A
this : FaithfulSMul G B
φ : B ≃ₐ[A] B
g : ↥(MulAction.stabilizer G ⊥)
hg : (Ideal.Quotient.stabilizerHom ⊥ ⊥ G) g = Ideal.Quotient.algEquivOfEqMap ⊥ φ ⋯
⊢ (MulSemiringAction.toAlgAut G A B) ↑g = φ

Tactic:
rw [AlgEquiv.ext_iff] at hg ⊢

Goal state after:
case h
G : Type u_1
inst✝⁸ : Group G
A : Type u_2
B : Type u_3
inst✝⁷ : CommRing A
inst✝⁶ : CommRing B
inst✝⁵ : IsDomain B
inst✝⁴ : Algebra A B
inst✝³ : FaithfulSMul A B
inst✝² : MulSemiringAction G B
inst✝¹ : IsGaloisGroup G A B
inst✝ : Finite G
this✝ : IsDomain A
this : FaithfulSMul G B
φ : B ≃ₐ[A] B
g : ↥(MulAction.stabilizer G ⊥)
hg : ∀ (a : B ⧸ ⊥), ((Ideal.Quotient.stabilizerHom ⊥ ⊥ G) g) a = (Ideal.Quotient.algEquivOfEqMap ⊥ φ ⋯) a
⊢ ∀ (a : B), ((MulSemiringAction.toAlgAut G A B) ↑g) a = φ a
Module: Mathlib.RingTheory.Trace.Basic

Goal state before:
pp: K : Type u_4
L : Type u_5
inst✝³ : Field K
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : FiniteDimensional K L
x : L
⊢ (Algebra.trace K L) x = finrank (↥K⟮x⟯) L • (Algebra.trace K ↥K⟮x⟯) (AdjoinSimple.gen K x)

Tactic:
by
  rw [← trace_trace (S := K⟮x⟯)]
  conv in x => rw [← AdjoinSimple.algebraMap_gen K x]
  rw [trace_algebraMap, LinearMap.map_smul_of_tower]

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

Goal state before:
pp: A₁ : Type u_7
B₁ : Type u_8
A₂ : Type u_9
B₂ : Type u_10
inst✝⁵ : CommRing A₁
inst✝⁴ : CommRing B₁
inst✝³ : CommRing A₂
inst✝² : CommRing B₂
inst✝¹ : Algebra A₁ B₁
inst✝ : Algebra A₂ B₂
e₁ : A₁ ≃+* A₂
e₂ : B₁ ≃+* B₂
he : (algebraMap A₂ B₂).comp ↑e₁ = (↑e₂).comp (algebraMap A₁ B₁)
x : B₁
this : Algebra A₁ B₂ := ((↑e₂).comp (algebraMap A₁ B₁)).toAlgebra
e' : B₁ ≃ₐ[A₁] B₂ := { toEquiv := e₂.toEquiv, map_mul' := ⋯, map_add' := ⋯, commutes' := ⋯ }
⊢ (trace A₁ B₁) x = e₁.symm ((trace A₂ B₂) (e₂ x))

Tactic:
rw [← Algebra.trace_eq_of_ringEquiv e₁ he, ← Algebra.trace_eq_of_algEquiv e',
    RingEquiv.symm_apply_apply]

Goal state after:
A₁ : Type u_7
B₁ : Type u_8
A₂ : Type u_9
B₂ : Type u_10
inst✝⁵ : CommRing A₁
inst✝⁴ : CommRing B₁
inst✝³ : CommRing A₂
inst✝² : CommRing B₂
inst✝¹ : Algebra A₁ B₁
inst✝ : Algebra A₂ B₂
e₁ : A₁ ≃+* A₂
e₂ : B₁ ≃+* B₂
he : (algebraMap A₂ B₂).comp ↑e₁ = (↑e₂).comp (algebraMap A₁ B₁)
x : B₁
this : Algebra A₁ B₂ := ((↑e₂).comp (algebraMap A₁ B₁)).toAlgebra
e' : B₁ ≃ₐ[A₁] B₂ := { toEquiv := e₂.toEquiv, map_mul' := ⋯, map_add' := ⋯, commutes' := ⋯ }
⊢ (trace A₁ B₂) (e' x) = (trace A₁ B₂) (e₂ x)
Module: Mathlib.RingTheory.Trace.Basic

Goal state before:
pp: K : Type u_4
L : Type u_5
inst✝¹¹ : Field K
inst✝¹⁰ : Field L
inst✝⁹ : Algebra K L
F : Type u_6
inst✝⁸ : Field F
inst✝⁷ : Algebra L F
inst✝⁶ : Algebra K F
inst✝⁵ : IsScalarTower K L F
E : Type u_7
inst✝⁴ : Field E
inst✝³ : Algebra K E
inst✝² : IsAlgClosed E
inst✝¹ : FiniteDimensional K F
inst✝ : Algebra.IsSeparable K F
pb : PowerBasis K L
this✝¹ : FiniteDimensional L F
this✝ : Algebra.IsSeparable L F
this : Fintype (L →ₐ[K] E) := PowerBasis.AlgHom.fintype pb
σ : F →ₐ[K] E
⊢ σ ((algebraMap L F) pb.gen) = (algHomEquivSigma σ).fst pb.gen

Tactic:
simp only [algHomEquivSigma, Equiv.coe_fn_mk, AlgHom.domRestrict, AlgHom.comp_apply,
      IsScalarTower.coe_toAlgHom']

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

Goal state before:
pp: R : Type u_2
inst✝² : CommRing R
inst✝¹ : IsDomain R
inst✝ : Fintype R
f g : R[X]
hf2 : f.degree = 2
hg2 : g.degree = 2
hR : Fintype.card R % 2 = 1
this : DecidableEq R := Classical.decEq R
hd : Disjoint (image (fun x ↦ eval x f) univ) (image (fun x ↦ eval x (-g)) univ)
⊢ 0 < f.degree

Tactic:
rw [hf2]

Goal state after:
R : Type u_2
inst✝² : CommRing R
inst✝¹ : IsDomain R
inst✝ : Fintype R
f g : R[X]
hf2 : f.degree = 2
hg2 : g.degree = 2
hR : Fintype.card R % 2 = 1
this : DecidableEq R := Classical.decEq R
hd : Disjoint (image (fun x ↦ eval x f) univ) (image (fun x ↦ eval x (-g)) univ)
⊢ 0 < 2
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
inst✝³ : Ring K
inst✝² : NoZeroDivisors K
inst✝¹ : Nontrivial K
G : Subgroup Kˣ
inst✝ : Fintype ↥G
n : ℕ := Fintype.card ↥G
⊢ ↑(Fintype.card ↥G) ≠ 0

Tactic:
intro nzero

Goal state after:
K : Type u_1
inst✝³ : Ring K
inst✝² : NoZeroDivisors K
inst✝¹ : Nontrivial K
G : Subgroup Kˣ
inst✝ : Fintype ↥G
n : ℕ := Fintype.card ↥G
nzero : ↑(Fintype.card ↥G) = 0
⊢ False
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
inst✝³ : Ring K
inst✝² : NoZeroDivisors K
inst✝¹ : Nontrivial K
G : Subgroup Kˣ
inst✝ : Fintype ↥G
n : ℕ := Fintype.card ↥G
nzero : ↑(Fintype.card ↥G) = 0
p : ℕ
char_p : CharP K p
⊢ False

Tactic:
have hd : p ∣ n := (CharP.cast_eq_zero_iff K p n).mp nzero

Goal state after:
K : Type u_1
inst✝³ : Ring K
inst✝² : NoZeroDivisors K
inst✝¹ : Nontrivial K
G : Subgroup Kˣ
inst✝ : Fintype ↥G
n : ℕ := Fintype.card ↥G
nzero : ↑(Fintype.card ↥G) = 0
p : ℕ
char_p : CharP K p
hd : p ∣ n
⊢ False
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
inst✝¹ : Field K
inst✝ : Fintype K
i : ℕ
x : Kˣ
hx : ∀ (x_1 : Kˣ), x_1 ∈ Subgroup.zpowers x
⊢ (∀ (x : Kˣ), x ^ i = 1) ↔ q - 1 ∣ i

Tactic:
rw [← Nat.card_eq_fintype_card, ← Nat.card_units, ← orderOf_eq_card_of_forall_mem_zpowers hx,
    orderOf_dvd_iff_pow_eq_one]

Goal state after:
K : Type u_1
inst✝¹ : Field K
inst✝ : Fintype K
i : ℕ
x : Kˣ
hx : ∀ (x_1 : Kˣ), x_1 ∈ Subgroup.zpowers x
⊢ (∀ (x : Kˣ), x ^ i = 1) ↔ x ^ i = 1
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
inst✝² : Field K
inst✝¹ : Fintype K
inst✝ : DecidableEq K
i : ℕ
φ : Kˣ →* K := { toFun := fun x ↦ ↑x ^ i, map_one' := ⋯, map_mul' := ⋯ }
this✝ : Decidable (φ = 1)
this : q - 1 ∣ i ↔ φ = 1
⊢ ↑(if φ = 1 then Fintype.card Kˣ else 0) = if q - 1 ∣ i then -1 else 0

Tactic:
simp only [this]
          split_ifs; swap
          · exact Nat.cast_zero
          · rw [Fintype.card_units, Nat.cast_sub,
              cast_card_eq_zero, Nat.cast_one, zero_sub]
            show 1 ≤ q; exact Fintype.card_pos_iff.mpr ⟨0⟩

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

Goal state before:
pp: K : Type u_1
R : Type u_2
inst✝³ : Field K
inst✝² : Fintype K
inst✝¹ : CommRing R
inst✝ : Algebra K R
x✝¹ x✝ : R
p : ℕ
left✝ : CharP K p
w✝ : ℕ+
hp : Nat.Prime p
card_eq : failed to pretty print expression (use 'set_option pp.rawOnError true' for raw representation)
a✝ : Nontrivial R
this✝ : CharP R p
this : ExpChar R p
⊢ failed to pretty print expression (use 'set_option pp.rawOnError true' for raw representation)

Tactic:
simp only [OneHom.toFun_eq_coe, MonoidHom.toOneHom_coe, powMonoidHom_apply, card_eq]

Goal state after:
K : Type u_1
R : Type u_2
inst✝³ : Field K
inst✝² : Fintype K
inst✝¹ : CommRing R
inst✝ : Algebra K R
x✝¹ x✝ : R
p : ℕ
left✝ : CharP K p
w✝ : ℕ+
hp : Nat.Prime p
card_eq : failed to pretty print expression (use 'set_option pp.rawOnError true' for raw representation)
a✝ : Nontrivial R
this✝ : CharP R p
this : ExpChar R p
⊢ (x✝¹ + x✝) ^ p ^ ↑w✝ = x✝¹ ^ p ^ ↑w✝ + x✝ ^ p ^ ↑w✝
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: x n : ℕ
h : x.Coprime n
⊢ x ^ φ n ≡ 1 [MOD n]

Tactic:
rw [← ZMod.natCast_eq_natCast_iff]
  let x' : Units (ZMod n) := ZMod.unitOfCoprime _ h
  have := ZMod.pow_totient x'
  apply_fun ((fun (x : Units (ZMod n)) => (x : ZMod n)) : Units (ZMod n) → ZMod n) at this
  simpa only [Nat.succ_eq_add_one, Nat.cast_pow, Units.val_one, Nat.cast_one,
    coe_unitOfCoprime, Units.val_pow_eq_pow_val]

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

Goal state before:
pp: case zero
p a : ℕ
⊢ (1 + p * a) ^ p ^ 0 ≡ 1 [MOD p ^ 0]

Tactic:
exact Nat.modEq_one

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 : F
ha : a ≠ 0
h₁ : a ^ (Fintype.card F - 1) = 1
⊢ a ^ (Fintype.card F / 2) = 1 ∨ a ^ (Fintype.card F / 2) = -1

Tactic:
← Nat.two_mul_odd_div_two (FiniteField.odd_card_of_char_ne_two hF),

Goal state after:
F : Type u_3
inst✝¹ : Field F
inst✝ : Fintype F
hF : ringChar F ≠ 2
a : F
ha : a ≠ 0
h₁ : a ^ (2 * (Fintype.card F / 2)) = 1
⊢ a ^ (Fintype.card F / 2) = 1 ∨ a ^ (Fintype.card F / 2) = -1
Module: Mathlib.RingTheory.Norm.Basic

Goal state before:
pp: case mp.refine_1
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : Ring S
inst✝⁴ : Algebra R S
inst✝³ : IsDomain R
inst✝² : IsDomain S
inst✝¹ : Free R S
inst✝ : Module.Finite R S
x : S
b : Basis (Free.ChooseBasisIndex R S) R S := Free.chooseBasis R S
decEq : DecidableEq (Free.ChooseBasisIndex R S) := Classical.decEq (Free.ChooseBasisIndex R S)
v : Free.ChooseBasisIndex R S → R
v_ne : v ≠ 0
hv : ⇑(b.repr (x * ∑ i, v i • b i)) = 0
i : Free.ChooseBasisIndex R S
⊢ (b.repr (x * ∑ i, v i • b i)) i = (b.repr 0) i

Tactic:
simpa only [map_zero, Pi.zero_apply] using! congr_fun hv i

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

Goal state before:
pp: case mp.refine_2
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : Ring S
inst✝⁴ : Algebra R S
inst✝³ : IsDomain R
inst✝² : IsDomain S
inst✝¹ : Free R S
inst✝ : Module.Finite R S
x : S
b : Basis (Free.ChooseBasisIndex R S) R S := Free.chooseBasis R S
decEq : DecidableEq (Free.ChooseBasisIndex R S) := Classical.decEq (Free.ChooseBasisIndex R S)
v : Free.ChooseBasisIndex R S → R
hv : ⇑(b.repr (x * ∑ i, v i • b i)) = 0
sum_eq : ∑ i, v i • b i = 0
⊢ v = 0

Tactic:
apply b.equivFun.symm.injective

Goal state after:
case mp.refine_2
R : Type u_1
S : Type u_2
inst✝⁶ : CommRing R
inst✝⁵ : Ring S
inst✝⁴ : Algebra R S
inst✝³ : IsDomain R
inst✝² : IsDomain S
inst✝¹ : Free R S
inst✝ : Module.Finite R S
x : S
b : Basis (Free.ChooseBasisIndex R S) R S := ⋯
decEq : DecidableEq (Free.ChooseBasisIndex R S) := ⋯
v : Free.ChooseBasisIndex R S → R
hv : ⇑(b.repr (x * ∑ i, v i • b i)) = 0
sum_eq : ∑ i, v i • b i = 0
⊢ b.equivFun.symm v = b.equivFun.symm 0
Module: Mathlib.RingTheory.UniqueFactorizationDomain.Multiplicative

Goal state before:
pp: case insert
α : Type u_1
inst✝² : CommMonoidWithZero α
inst✝¹ : UniqueFactorizationMonoid α
β : Type u_3
inst✝ : CommMonoidWithZero β
f : α → β
i j : α → ℕ
h1 : ∀ {x y : α}, IsUnit y → f (x * y) = f x * f y
hpr : ∀ {p : α} (i : ℕ), Prime p → f (p ^ i) = f p ^ i
hcp : ∀ {x y : α}, IsRelPrime x y → f (x * y) = f x * f y
this : DecidableEq α := Classical.decEq α
p : α
s : Finset α
hps : p ∉ s
ih :
  (∀ p ∈ s, Prime p) →
    (∀ p ∈ s, ∀ q ∈ s, p ∣ q → p = q) → f (∏ p ∈ s, p ^ (i p + j p)) = f (∏ p ∈ s, p ^ i p) * f (∏ p ∈ s, p ^ j p)
is_prime : ∀ p_1 ∈ insert p s, Prime p_1
is_coprime : ∀ p_1 ∈ insert p s, ∀ q ∈ insert p s, p_1 ∣ q → p_1 = q
hpr_p : Prime p
hpr_s : ∀ p ∈ s, Prime p
⊢ f (∏ p ∈ insert p s, p ^ (i p + j p)) = f (∏ p ∈ insert p s, p ^ i p) * f (∏ p ∈ insert p s, p ^ j p)

Tactic:
have hcp_p := fun i => prime_pow_coprime_prod_of_coprime_insert i p hps is_prime is_coprime

Goal state after:
case insert
α : Type u_1
inst✝² : CommMonoidWithZero α
inst✝¹ : UniqueFactorizationMonoid α
β : Type u_3
inst✝ : CommMonoidWithZero β
f : α → β
i j : α → ℕ
h1 : ∀ {x y : α}, IsUnit y → f (x * y) = f x * f y
hpr : ∀ {p : α} (i : ℕ), Prime p → f (p ^ i) = f p ^ i
hcp : ∀ {x y : α}, IsRelPrime x y → f (x * y) = f x * f y
this : DecidableEq α := Classical.decEq α
p : α
s : Finset α
hps : p ∉ s
ih :
  (∀ p ∈ s, Prime p) →
    (∀ p ∈ s, ∀ q ∈ s, p ∣ q → p = q) → f (∏ p ∈ s, p ^ (i p + j p)) = f (∏ p ∈ s, p ^ i p) * f (∏ p ∈ s, p ^ j p)
is_prime : ∀ p_1 ∈ insert p s, Prime p_1
is_coprime : ∀ p_1 ∈ insert p s, ∀ q ∈ insert p s, p_1 ∣ q → p_1 = q
hpr_p : Prime p
hpr_s : ∀ p ∈ s, Prime p
hcp_p : ∀ (i : α → ℕ), IsRelPrime (p ^ i p) (∏ p' ∈ s, p' ^ i p')
⊢ f (∏ p ∈ insert p s, p ^ (i p + j p)) = f (∏ p ∈ insert p s, p ^ i p) * f (∏ p ∈ insert p s, p ^ j p)