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

Goal state before:
pp: F : Type u
E : Type v
inst✝⁷ : Field F
inst✝⁶ : Field E
inst✝⁵ : Algebra F E
K : Type w
inst✝⁴ : Field K
inst✝³ : Algebra F K
inst✝² : Algebra E K
inst✝¹ : IsScalarTower F E K
inst✝ : Algebra.IsSeparable F E
x : K
hsep : IsSeparable E x
f : E[X] := minpoly E x
hf : f = minpoly E x
E' : IntermediateField F E := adjoin F ↑f.coeffs
this : FiniteDimensional F ↥E'
⊢ IsSeparable F x

Tactic:
let g : E'[X] := f.toSubring E'.toSubring (subset_adjoin F _)

Goal state after:
F : Type u
E : Type v
inst✝⁷ : Field F
inst✝⁶ : Field E
inst✝⁵ : Algebra F E
K : Type w
inst✝⁴ : Field K
inst✝³ : Algebra F K
inst✝² : Algebra E K
inst✝¹ : IsScalarTower F E K
inst✝ : Algebra.IsSeparable F E
x : K
hsep : IsSeparable E x
f : E[X] := minpoly E x
hf : f = minpoly E x
E' : IntermediateField F E := adjoin F ↑f.coeffs
this : FiniteDimensional F ↥E'
g : (↥E')[X] := f.toSubring E'.toSubring ⋯
⊢ IsSeparable F x
Module: Mathlib.FieldTheory.KrullTopology

Goal state before:
pp: K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : Algebra.IsIntegral K L
f g : Gal(L/K)
hfg : f ≠ g
φ : Gal(L/K) := f⁻¹ * g
x : L
hx : f x ≠ g x
hφx : φ x ≠ x
E : IntermediateField K L := K⟮x⟯
h_findim : FiniteDimensional K ↥E := IntermediateField.adjoin.finiteDimensional (Algebra.IsIntegral.isIntegral x)
H : Subgroup Gal(L/K) := E.fixingSubgroup
h_basis : ↑H ∈ galGroupBasis K L
h_nhds : ↑H ∈ 𝓝 1
⊢ (fun x y ↦ ∃ u v, IsOpen u ∧ IsOpen v ∧ x ∈ u ∧ y ∈ v ∧ Disjoint u v) f g

Tactic:
mem_nhds_iff

Goal state after:
K : Type u_1
L : Type u_2
inst✝³ : Field K
inst✝² : Field L
inst✝¹ : Algebra K L
inst✝ : Algebra.IsIntegral K L
f g : Gal(L/K)
hfg : f ≠ g
φ : Gal(L/K) := f⁻¹ * g
x : L
hx : f x ≠ g x
hφx : φ x ≠ x
E : IntermediateField K L := K⟮x⟯
h_findim : FiniteDimensional K ↥E := IntermediateField.adjoin.finiteDimensional (Algebra.IsIntegral.isIntegral x)
H : Subgroup Gal(L/K) := E.fixingSubgroup
h_basis : ↑H ∈ galGroupBasis K L
h_nhds : ∃ t ⊆ ↑H, IsOpen t ∧ 1 ∈ t
⊢ (fun x y ↦ ∃ u v, IsOpen u ∧ IsOpen v ∧ x ∈ u ∧ y ∈ v ∧ Disjoint u v) f g
Module: Mathlib.FieldTheory.Galois.Basic

Goal state before:
pp: case right
F : Type u_1
inst✝⁴ : Field F
E : Type u_2
inst✝³ : Field E
inst✝² : Algebra F E
K L : IntermediateField F E
inst✝¹ : IsGalois F ↥K
inst✝ : FiniteDimensional F ↥K
h : K ⊔ L = ⊤
T : F[X]
hT₁ : T.Separable
hT₂ : (Polynomial.map (algebraMap F ↥K) T).Splits ∧ lift (adjoin F (T.rootSet ↥K)) = lift ⊤
T' : (↥L)[X] := Polynomial.map (algebraMap F ↥L) T
h' : T'.rootSet E = T.rootSet E
⊢ adjoin (↥L) (T'.rootSet E) = ⊤

Tactic:
lift_adjoin,

Goal state after:
case right
F : Type u_1
inst✝⁴ : Field F
E : Type u_2
inst✝³ : Field E
inst✝² : Algebra F E
K L : IntermediateField F E
inst✝¹ : IsGalois F ↥K
inst✝ : FiniteDimensional F ↥K
h : K ⊔ L = ⊤
T : F[X]
hT₁ : T.Separable
hT₂ : (Polynomial.map (algebraMap F ↥K) T).Splits ∧ adjoin F (Subtype.val '' T.rootSet ↥K) = lift ⊤
T' : (↥L)[X] := Polynomial.map (algebraMap F ↥L) T
h' : T'.rootSet E = T.rootSet E
⊢ adjoin (↥L) (T'.rootSet E) = ⊤
Module: Mathlib.FieldTheory.Galois.Basic

Goal state before:
pp: case right
F : Type u_1
inst✝⁴ : Field F
E : Type u_2
inst✝³ : Field E
inst✝² : Algebra F E
K L : IntermediateField F E
inst✝¹ : IsGalois F ↥K
inst✝ : FiniteDimensional F ↥K
h : K ⊔ L = ⊤
T : F[X]
hT₁ : T.Separable
hT₂ : (Polynomial.map (algebraMap F ↥K) T).Splits ∧ adjoin F (T.rootSet E) = lift ⊤
T' : (↥L)[X] := Polynomial.map (algebraMap F ↥L) T
h' : T'.rootSet E = T.rootSet E
⊢ L ⊔ K = ⊤

Tactic:
sup_comm,

Goal state after:
case right
F : Type u_1
inst✝⁴ : Field F
E : Type u_2
inst✝³ : Field E
inst✝² : Algebra F E
K L : IntermediateField F E
inst✝¹ : IsGalois F ↥K
inst✝ : FiniteDimensional F ↥K
h : K ⊔ L = ⊤
T : F[X]
hT₁ : T.Separable
hT₂ : (Polynomial.map (algebraMap F ↥K) T).Splits ∧ adjoin F (T.rootSet E) = lift ⊤
T' : (↥L)[X] := Polynomial.map (algebraMap F ↥L) T
h' : T'.rootSet E = T.rootSet E
⊢ K ⊔ L = ⊤
Module: Mathlib.FieldTheory.Galois.Basic

Goal state before:
pp: F : Type u_1
E' : Type u_3
inst✝³ : Field F
inst✝² : Field E'
inst✝¹ : Algebra F E'
inst✝ : IsGalois F E'
L : IntermediateField F E'
hnfd : FiniteDimensional F ↥L
E : IntermediateField F E' := normalClosure F (↥L) E'
hle : L ≤ E
L' : IntermediateField F ↥E := restrict hle
h : finrank F ↥L' * finrank ↥L' ↥E = finrank F ↥E
⊢ finrank F ↥L = L.fixingSubgroup.index

Tactic:
classical
  rw [← IsGalois.card_fixingSubgroup_eq_finrank L', ← IsGalois.card_aut_eq_finrank F E] at h
  rw [← L'.fixingSubgroup.index_mul_card, Nat.mul_left_inj Finite.card_pos.ne'] at h
  rw [(restrictAlgEquiv hle).toLinearEquiv.finrank_eq, h, ← L'.map_fixingSubgroup_index E']
  congr 2
  exact lift_restrict hle

Goal state after:
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
s : S
P : R[X]
hmo : P.Monic
hP : (Polynomial.aeval s) P = 0
Pmin : ∀ (Q : R[X]), Q.Monic → (Polynomial.aeval s) Q = 0 → P.degree ≤ Q.degree
hs : IsIntegral R s
hnz : ¬minpoly R s - P = 0
⊢ (minpoly R s - P).degree < (minpoly R s).degree

Tactic:
refine degree_sub_lt_left ?_ (ne_zero hs) ?_

Goal state after:
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]
hmo : P.Monic
hP : (Polynomial.aeval s) P = 0
Pmin : ∀ (Q : R[X]), Q.Monic → (Polynomial.aeval s) Q = 0 → P.degree ≤ Q.degree
hs : IsIntegral R s
hnz : ¬minpoly R s - P = 0
⊢ (minpoly R s).degree = P.degree

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]
hmo : P.Monic
hP : (Polynomial.aeval s) P = 0
Pmin : ∀ (Q : R[X]), Q.Monic → (Polynomial.aeval s) Q = 0 → P.degree ≤ Q.degree
hs : IsIntegral R s
hnz : ¬minpoly R s - P = 0
⊢ (minpoly R s).leadingCoeff = P.leadingCoeff
Module: Mathlib.FieldTheory.Minpoly.MinpolyDiv

Goal state before:
pp: case neg
R : Type u_2
S : Type u_1
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
x : S
a✝ : Nontrivial S
hx : ¬IsIntegral R x
⊢ (minpolyDiv R x).natDegree = (minpoly R x).natDegree - 1

Tactic:
· rw [minpolyDiv_eq_zero hx, minpoly.eq_zero hx]; rfl

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
h : IsOpen L.fixingSubgroup.carrier
⊢ FiniteDimensional k ↥L

Tactic:
have : (IntermediateFieldEquivClosedSubgroup.toFun L).carrier ∈ nhds 1 :=
    IsOpen.mem_nhds h (congrFun rfl)

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
h : IsOpen L.fixingSubgroup.carrier
this : (↑(IntermediateFieldEquivClosedSubgroup.toFun L)).carrier ∈ nhds 1
⊢ FiniteDimensional k ↥L
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
n : ℕ
hn : finrank (↥F⟮x⟯) E = q ^ n
⊢ finrank F ↥F⟮x⟯ * finrank (↥F⟮x⟯) E = q ^ (m + n)

Tactic:
hn,

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
n : ℕ
hn : finrank (↥F⟮x⟯) E = q ^ n
⊢ finrank F ↥F⟮x⟯ * q ^ n = q ^ (m + n)
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
inst✝² : IsPurelyInseparable F E
L : Type u_2
inst✝¹ : CommRing L
inst✝ : IsReduced L
f g : E →+* L
x : E
q : ℕ := ringExpChar F
n : ℕ
y : F
h : (algebraMap F E) y = x ^ q ^ n
heq : ((fun f ↦ f.comp (algebraMap F E)) f) y = ((fun f ↦ f.comp (algebraMap F E)) g) y
⊢ f x = g x

Tactic:
simp_rw [RingHom.comp_apply, h, map_pow] at heq

Goal state after:
F : Type u
E : Type v
inst✝⁵ : Field F
inst✝⁴ : Field E
inst✝³ : Algebra F E
inst✝² : IsPurelyInseparable F E
L : Type u_2
inst✝¹ : CommRing L
inst✝ : IsReduced L
f g : E →+* L
x : E
q : ℕ := ringExpChar F
n : ℕ
y : F
h : (algebraMap F E) y = x ^ q ^ n
heq : f x ^ q ^ n = g x ^ q ^ n
⊢ f x = g x
Module: Mathlib.FieldTheory.PurelyInseparable.Basic

Goal state before:
pp: 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
⊢ ∀ {a b : A},
    a ∈ {x | ∃ n, x ^ p ^ n ∈ (algebraMap R A).rangeS} →
      b ∈ {x | ∃ n, x ^ p ^ n ∈ (algebraMap R A).rangeS} → a * b ∈ {x | ∃ n, x ^ p ^ n ∈ (algebraMap R A).rangeS}

Tactic:
rintro x y ⟨n, hx⟩ ⟨m, hy⟩
    use n + m
    rw [mul_pow, pow_add, pow_mul, mul_comm (_ ^ n), pow_mul]
    exact mul_mem (pow_mem hx _) (pow_mem hy _)

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

Goal state before:
pp: G : Type u_1
A : Type u_2
B : Type u_3
K : Type u_4
L : Type u_5
inst✝¹⁸ : Group G
inst✝¹⁷ : CommRing A
inst✝¹⁶ : CommRing B
inst✝¹⁵ : MulSemiringAction G B
inst✝¹⁴ : Algebra A B
inst✝¹³ : Field K
inst✝¹² : Field L
inst✝¹¹ : Algebra K L
inst✝¹⁰ : Algebra A K
inst✝⁹ : Algebra B L
inst✝⁸ : Algebra A L
inst✝⁷ : IsFractionRing A K
inst✝⁶ : IsFractionRing B L
inst✝⁵ : IsScalarTower A K L
inst✝⁴ : IsScalarTower A B L
inst✝³ : MulSemiringAction G L
inst✝² : SMulDistribClass G B L
hGKL : IsGaloisGroup G K L
inst✝¹ : IsIntegrallyClosed A
inst✝ : Algebra.IsIntegral A B
hc : ∀ (a : A), (algebraMap K L) ((algebraMap A K) a) = (algebraMap B L) ((algebraMap A B) a)
x : B
h : ∀ (g : G), g • x = x
⊢ ∀ (g : G), g • (algebraMap B L) x = (algebraMap B L) x

Tactic:
simpa [← algebraMap.coe_smul']

Goal state after:
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 ↥K⟮x⟯) (finrank (↥K⟮x⟯) L • AdjoinSimple.gen K x) =
    finrank (↥K⟮x⟯) L • (Algebra.trace K ↥K⟮x⟯) (AdjoinSimple.gen K x)

Tactic:
LinearMap.map_smul_of_tower

Goal state after:
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
⊢ finrank (↥K⟮x⟯) L • (Algebra.trace K ↥K⟮x⟯) (AdjoinSimple.gen K x) =
    finrank (↥K⟮x⟯) L • (Algebra.trace K ↥K⟮x⟯) (AdjoinSimple.gen K x)
Module: Mathlib.RingTheory.Invariant.Basic

Goal state before:
pp: B : Type u_2
inst✝⁴ : CommRing B
G : Type u_3
inst✝³ : Group G
inst✝² : Finite G
inst✝¹ : MulSemiringAction G B
Q : Ideal B
inst✝ : Q.IsPrime
val✝ : Fintype G
P : Ideal B := {g | g • Q ≠ Q}.inf fun g ↦ g • Q
g : G
hg1 : g ∈ {g | g • Q ≠ Q}
hg2 : g • Q ≤ Q
⊢ False

Tactic:
exact (Finset.mem_filter.mp hg1).2 (smul_eq_of_smul_le hg2)

Goal state after:
Module: Mathlib.Data.ZMod.ValMinAbs

Goal state before:
pp: case pos
k n : ℕ
h✝¹ : k = n + 1
x : ZMod (namedPattern k (n + 1) h✝¹)
h✝ : x.val ≤ namedPattern k (n + 1) h✝¹ / 2
⊢ ↑↑x.val = x

Tactic:
Int.cast_natCast,

Goal state after:
case pos
k n : ℕ
h✝¹ : k = n + 1
x : ZMod (namedPattern k (n + 1) h✝¹)
h✝ : x.val ≤ namedPattern k (n + 1) h✝¹ / 2
⊢ ↑x.val = x
Module: Mathlib.Data.ZMod.ValMinAbs

Goal state before:
pp: case neg
k n : ℕ
h✝¹ : k = n + 1
x : ZMod (namedPattern k (n + 1) h✝¹)
h✝ : ¬x.val ≤ namedPattern k (n + 1) h✝¹ / 2
⊢ ↑↑x.val - ↑↑(namedPattern k (n + 1) h✝¹) = x

Tactic:
Int.cast_natCast,

Goal state after:
case neg
k n : ℕ
h✝¹ : k = n + 1
x : ZMod (namedPattern k (n + 1) h✝¹)
h✝ : ¬x.val ≤ namedPattern k (n + 1) h✝¹ / 2
⊢ ↑x.val - ↑↑(namedPattern k (n + 1) h✝¹) = x
Module: Mathlib.Data.ZMod.ValMinAbs

Goal state before:
pp: case neg
k n : ℕ
h✝¹ : k = n + 1
x : ZMod (namedPattern k (n + 1) h✝¹)
h✝ : ¬x.val ≤ namedPattern k (n + 1) h✝¹ / 2
⊢ x - ↑↑(namedPattern k (n + 1) h✝¹) = x

Tactic:
Int.cast_natCast,

Goal state after:
case neg
k n : ℕ
h✝¹ : k = n + 1
x : ZMod (namedPattern k (n + 1) h✝¹)
h✝ : ¬x.val ≤ namedPattern k (n + 1) h✝¹ / 2
⊢ x - ↑(namedPattern k (n + 1) h✝¹) = x
Module: Mathlib.Data.ZMod.ValMinAbs

Goal state before:
pp: case neg
n : ℕ
inst✝ : NeZero n
a : ZMod n
this : ↑a.val - ↑n ≤ 0
h✝ : ¬a.val ≤ n / 2
⊢ -(↑↑a.val - ↑↑n) = -a

Tactic:
Int.cast_natCast,

Goal state after:
case neg
n : ℕ
inst✝ : NeZero n
a : ZMod n
this : ↑a.val - ↑n ≤ 0
h✝ : ¬a.val ≤ n / 2
⊢ -(↑a.val - ↑↑n) = -a
Module: Mathlib.Data.ZMod.ValMinAbs

Goal state before:
pp: case neg
n : ℕ
inst✝ : NeZero n
a : ZMod n
this : ↑a.val - ↑n ≤ 0
h✝ : ¬a.val ≤ n / 2
⊢ -(↑a.val - ↑↑n) = -a

Tactic:
Int.cast_natCast,

Goal state after:
case neg
n : ℕ
inst✝ : NeZero n
a : ZMod n
this : ↑a.val - ↑n ≤ 0
h✝ : ¬a.val ≤ n / 2
⊢ -(↑a.val - ↑n) = -a
Module: Mathlib.Data.ZMod.ValMinAbs

Goal state before:
pp: n : ℕ
hpos : NeZero n
a : ZMod n
⊢ a.valMinAbs.natAbs = min a.val (n - a.val)

Tactic:
by
  rw [valMinAbs_def_pos]
  have := a.val_lt
  omega

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

Goal state before:
pp: case pos.succ.prime
K : Type u_4
L : Type u_5
inst✝² : Field K
inst✝¹ : Field L
inst✝ : Algebra K L
H : ¬Algebra.IsSeparable K L
p : ℕ
this : p ≠ 0
h₀ : FiniteDimensional K L
x : ↥(separableClosure K L)
n : ℕ
hn : finrank (↥(separableClosure K L)) L = p ^ (n + 1)
hprime : Nat.Prime p
hchar✝ : CharP K p
⊢ (trace K ↥(separableClosure K L)) (finrank (↥(separableClosure K L)) L • x) =
    0 ((algebraMap (↥(separableClosure K L)) L) x)

Tactic:
hn,

Goal state after:
case pos.succ.prime
K : Type u_4
L : Type u_5
inst✝² : Field K
inst✝¹ : Field L
inst✝ : Algebra K L
H : ¬Algebra.IsSeparable K L
p : ℕ
this : p ≠ 0
h₀ : FiniteDimensional K L
x : ↥(separableClosure K L)
n : ℕ
hn : finrank (↥(separableClosure K L)) L = p ^ (n + 1)
hprime : Nat.Prime p
hchar✝ : CharP K p
⊢ (trace K ↥(separableClosure K L)) (p ^ (n + 1) • x) = 0 ((algebraMap (↥(separableClosure K L)) L) x)
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
inst✝² : Ring K
inst✝¹ : NoZeroDivisors K
G : Subgroup Kˣ
inst✝ : Fintype ↥G
a : ↥G
ha : a ≠ 1
a_mul_emb : ↥G ↪ ↥G := mulLeftEmbedding a
h_unchanged : map a_mul_emb univ = univ
h_sum_map : ∑ x, ↑↑x = ↑↑a * ∑ x, ↑↑x
⊢ ↑↑a * ∑ x, ↑↑x - 1 * ∑ x, ↑↑x = 0

Tactic:
← h_sum_map,

Goal state after:
K : Type u_1
inst✝² : Ring K
inst✝¹ : NoZeroDivisors K
G : Subgroup Kˣ
inst✝ : Fintype ↥G
a : ↥G
ha : a ≠ 1
a_mul_emb : ↥G ↪ ↥G := mulLeftEmbedding a
h_unchanged : map a_mul_emb univ = univ
h_sum_map : ∑ x, ↑↑x = ↑↑a * ∑ x, ↑↑x
⊢ ∑ x, ↑↑x - 1 * ∑ x, ↑↑x = 0
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
inst✝¹ : Field K
inst✝ : Fintype K
aux : X ^ q - X ≠ 0
this : (X ^ q - X).roots.toFinset = univ
⊢ (X ^ q - X).roots.Nodup

Tactic:
apply nodup_roots

Goal state after:
K : Type u_1
inst✝¹ : Field K
inst✝ : Fintype K
aux : X ^ q - X ≠ 0
this : (X ^ q - X).roots.toFinset = univ
⊢ (X ^ q - X).Separable
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
inst✝¹ : Field K
inst✝ : Fintype K
f : K[X]
p : ℕ
hp✝ : CharP K p
n : ℕ
npos : 0 < n
hp : Nat.Prime p
hn : q = p ^ n
this : Fact (Nat.Prime p)
⊢ (expand K q) f = f ^ q

Tactic:
hn,

Goal state after:
K : Type u_1
inst✝¹ : Field K
inst✝ : Fintype K
f : K[X]
p : ℕ
hp✝ : CharP K p
n : ℕ
npos : 0 < n
hp : Nat.Prime p
hn : q = p ^ n
this : Fact (Nat.Prime p)
⊢ (expand K (p ^ n)) f = f ^ p ^ n
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: case inl.«0»
hp : Fact (Nat.Prime 2)
⊢ ∃ a b, a ^ 2 + b ^ 2 = (fun i ↦ i) ⟨0, ⋯⟩

Tactic:
use 0

Goal state after:
case h
hp : Fact (Nat.Prime 2)
⊢ ∃ b, 0 ^ 2 + b ^ 2 = (fun i ↦ i) ⟨0, ⋯⟩
Module: Mathlib.RingTheory.ZMod

Goal state before:
pp: n : ℕ
x✝ : ℤ
⊢ x✝ ∈ RingHom.ker (Int.castRingHom (ZMod n)) ↔ x✝ ∈ Ideal.span {↑n}

Tactic:
rw [Ideal.mem_span_singleton, RingHom.mem_ker, Int.coe_castRingHom,
    ZMod.intCast_zmod_eq_zero_iff_dvd]

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

Goal state before:
pp: case pos
p x y : ℕ
hp : Nat.Prime p
h : (p - 1) * ((x - y) / (p - 1)) = x - y
hxy : y ≤ x
hy : 0 < y
n : ℤ
hn : n ≡ 0 [ZMOD ↑p]
⊢ n ^ x ≡ n ^ y [ZMOD ↑p]

Tactic:
hn,

Goal state after:
case pos
p x y : ℕ
hp : Nat.Prime p
h : (p - 1) * ((x - y) / (p - 1)) = x - y
hxy : y ≤ x
hy : 0 < y
n : ℤ
hn : n ≡ 0 [ZMOD ↑p]
⊢ 0 ^ x ≡ 0 ^ y [ZMOD ↑p]
Module: Mathlib.FieldTheory.Finite.Basic

Goal state before:
pp: K : Type u_1
R : Type u_2
F : Type u_3
inst✝² : Field F
p : ℕ
inst✝¹ : Fact (Nat.Prime p)
inst✝ : CharP F p
x✝ : F
⊢ x✝ ∈ Finset.map { toFun := ⇑(castHom ⋯ F), inj' := ⋯ } univ ↔ x✝ ∈ ⊥

Tactic:
by simp_rw [Finset.mem_map, mem_univ, true_and, ← fieldRange_castHom_eq_bot p]; rfl

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

Goal state before:
pp: case mpr
F : Type u_3
inst✝¹ : Field F
inst✝ : Fintype F
hF : ringChar F ≠ 2
g : Fˣ
hg : ∀ (x : Fˣ), x ∈ Subgroup.zpowers g
hodd : 2 * (Nat.card F / 2) = Nat.card F - 1
this : 0 < Nat.card F / 2
m : ℕ
h : (fun x ↦ g ^ x) (2 * m) ^ (Nat.card F / 2) = 1
key : 2 * (Nat.card F / 2) ∣ 2 * m * (Nat.card F / 2)
⊢ IsSquare ((fun x ↦ g ^ x) (2 * m))

Tactic:
refine ⟨g ^ m, ?_⟩

Goal state after:
case mpr
F : Type u_3
inst✝¹ : Field F
inst✝ : Fintype F
hF : ringChar F ≠ 2
g : Fˣ
hg : ∀ (x : Fˣ), x ∈ Subgroup.zpowers g
hodd : 2 * (Nat.card F / 2) = Nat.card F - 1
this : 0 < Nat.card F / 2
m : ℕ
h : (fun x ↦ g ^ x) (2 * m) ^ (Nat.card F / 2) = 1
key : 2 * (Nat.card F / 2) ∣ 2 * m * (Nat.card F / 2)
⊢ (fun x ↦ g ^ x) (2 * m) = g ^ m * g ^ m
Module: Mathlib.RingTheory.Ideal.Norm.AbsNorm

Goal state before:
pp: S : Type u_1
inst✝¹ : CommRing S
P : Ideal S
P_prime : P.IsPrime
inst✝ : IsDedekindDomain S
hP : P ≠ ⊥
i : ℕ
⊢ cardQuot (P ^ i) = cardQuot P ^ i

Tactic:
induction i with
  | zero => simp
  | succ i ih => ?_

Goal state after:
case succ
S : Type u_1
inst✝¹ : CommRing S
P : Ideal S
P_prime : P.IsPrime
inst✝ : IsDedekindDomain S
hP : P ≠ ⊥
i : ℕ
ih : cardQuot (P ^ i) = cardQuot P ^ i
⊢ cardQuot (P ^ (i + 1)) = cardQuot P ^ (i + 1)
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
⊢ (Algebra.norm ℤ) x = 0

Tactic:
← Int.natAbs_eq_zero,

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
⊢ ((Algebra.norm ℤ) x).natAbs = 0
Module: Mathlib.GroupTheory.Submonoid.Inverses

Goal state before:
pp: M : Type u_1
inst✝ : Monoid M
S : Submonoid M
hS : S ≤ IsUnit.submonoid M
x : M
hx : x ∈ S
this : x = ↑(IsUnit.unit ⋯)⁻¹⁻¹
⊢ ↑(IsUnit.unit ⋯)⁻¹⁻¹ ∈ S.leftInv.leftInv

Tactic:
exact S.leftInv.unit_mem_leftInv _ (S.unit_mem_leftInv _ hx)

Goal state after:
Module: Mathlib.RingTheory.Localization.InvSubmonoid

Goal state before:
pp: R : Type u_1
inst✝⁴ : CommRing R
M : Submonoid R
S : Type u_2
inst✝³ : CommRing S
inst✝² : Algebra R S
inst✝¹ : IsLocalization M S
inst✝ : Monoid.FG ↥M
s : Finset S
hs : Submonoid.closure ↑s = invSubmonoid M S
x : S
⊢ x ∈ ↑(Submodule.span R ↑(Submonoid.closure ↑s))

Tactic:
hs,

Goal state after:
R : Type u_1
inst✝⁴ : CommRing R
M : Submonoid R
S : Type u_2
inst✝³ : CommRing S
inst✝² : Algebra R S
inst✝¹ : IsLocalization M S
inst✝ : Monoid.FG ↥M
s : Finset S
hs : Submonoid.closure ↑s = invSubmonoid M S
x : S
⊢ x ∈ ↑(Submodule.span R ↑(invSubmonoid M S))
Module: Mathlib.RingTheory.Unramified.Basic

Goal state before:
pp: 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
⊢ (Ideal.Quotient.mkₐ R I).comp g₁ = (Ideal.Quotient.mkₐ R I).comp g₂

Tactic:
apply h₂

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
⊢ (Ideal.Quotient.mkₐ R (Ideal.map (Ideal.Quotient.mk I) J)).comp ((Ideal.Quotient.mkₐ R I).comp g₁) =
    (Ideal.Quotient.mkₐ R (Ideal.map (Ideal.Quotient.mk I) J)).comp ((Ideal.Quotient.mkₐ R I).comp g₂)
Module: Mathlib.RingTheory.QuasiFinite.Basic

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Algebra R S
p : Ideal R
inst✝⁴ : p.IsPrime
q : Ideal S
inst✝³ : q.IsPrime
inst✝² : q.LiesOver p
inst✝¹ : EssFiniteType R S
inst✝ : QuasiFiniteAt R q
e : ↑(PrimeSpectrum.comap (algebraMap R S) ⁻¹' {{ asIdeal := p, isPrime := ⋯ }}) ≃ₜ
  PrimeSpectrum ({ asIdeal := p, isPrime := ⋯ }.asIdeal.Fiber S) :=
  PrimeSpectrum.preimageHomeomorphFiber R S { asIdeal := p, isPrime := ⋯ }
qF : PrimeSpectrum (p.Fiber S) := e ⟨{ asIdeal := q, isPrime := inst✝³ }, ⋯⟩
this✝ : QuasiFiniteAt p.ResidueField qF.asIdeal
r : p.Fiber S
hr : r ∉ qF.asIdeal
hrq : ↑(PrimeSpectrum.basicOpen r) = {{ asIdeal := qF.asIdeal, isPrime := ⋯ }}
s : R
hs : s ∉ p
x : S
hsx : s • r = 1 ⊗ₜ[R] x
this :
  r ∉
    ((PrimeSpectrum.preimageEquivFiber R S { asIdeal := p, isPrime := ⋯ })
        ⟨{ asIdeal := q, isPrime := inst✝³ }, ⋯⟩).asIdeal
⊢ x ∉ q

Tactic:
PrimeSpectrum.preimageEquivFiber_apply_asIdeal,

Goal state after:
R : Type u_1
S : Type u_2
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Algebra R S
p : Ideal R
inst✝⁴ : p.IsPrime
q : Ideal S
inst✝³ : q.IsPrime
inst✝² : q.LiesOver p
inst✝¹ : EssFiniteType R S
inst✝ : QuasiFiniteAt R q
e : ↑(PrimeSpectrum.comap (algebraMap R S) ⁻¹' {{ asIdeal := p, isPrime := ⋯ }}) ≃ₜ
  PrimeSpectrum ({ asIdeal := p, isPrime := ⋯ }.asIdeal.Fiber S) :=
  PrimeSpectrum.preimageHomeomorphFiber R S { asIdeal := p, isPrime := ⋯ }
qF : PrimeSpectrum (p.Fiber S) := e ⟨{ asIdeal := q, isPrime := inst✝³ }, ⋯⟩
this✝ : QuasiFiniteAt p.ResidueField qF.asIdeal
r : p.Fiber S
hr : r ∉ qF.asIdeal
hrq : ↑(PrimeSpectrum.basicOpen r) = {{ asIdeal := qF.asIdeal, isPrime := ⋯ }}
s : R
hs : s ∉ p
x : S
hsx : s • r = 1 ⊗ₜ[R] x
this :
  r ∉
    RingHom.ker
      (TensorProduct.lift
          (Ideal.ResidueField.mapₐ { asIdeal := p, isPrime := ⋯ }.asIdeal
            (↑⟨{ asIdeal := q, isPrime := inst✝³ }, ⋯⟩).asIdeal (ofId R S) ⋯)
          (IsScalarTower.toAlgHom R S (↑⟨{ asIdeal := q, isPrime := inst✝³ }, ⋯⟩).asIdeal.ResidueField) ⋯).toRingHom
⊢ x ∉ q