mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.RingTheory.Unramified.Basic

Goal state before:
pp: R : Type v
inst✝³ : CommRing R
A : Type u
inst✝² : CommRing A
inst✝¹ : Algebra R A
inst✝ : Small.{w, u} A
⊢ FormallyUnramified R A ↔
    ∀ ⦃B : Type w⦄ [inst : CommRing B] [inst_1 : Algebra R B] (I : Ideal B),
      I ^ 2 = ⊥ → Function.Injective (Ideal.Quotient.mkₐ R I).comp

Tactic:
constructor

Goal state after:
case mp
R : Type v
inst✝³ : CommRing R
A : Type u
inst✝² : CommRing A
inst✝¹ : Algebra R A
inst✝ : Small.{w, u} A
⊢ FormallyUnramified R A →
    ∀ ⦃B : Type w⦄ [inst : CommRing B] [inst_1 : Algebra R B] (I : Ideal B),
      I ^ 2 = ⊥ → Function.Injective (Ideal.Quotient.mkₐ R I).comp

case mpr
R : Type v
inst✝³ : CommRing R
A : Type u
inst✝² : CommRing A
inst✝¹ : Algebra R A
inst✝ : Small.{w, u} A
⊢ (∀ ⦃B : Type w⦄ [inst : CommRing B] [inst_1 : Algebra R B] (I : Ideal B),
      I ^ 2 = ⊥ → Function.Injective (Ideal.Quotient.mkₐ R I).comp) →
    FormallyUnramified R A
Module: Mathlib.RingTheory.Unramified.Basic

Goal state before:
pp: case mpr
R : Type v
inst✝³ : CommRing R
A : Type u
inst✝² : CommRing A
inst✝¹ : Algebra R A
inst✝ : Small.{w, u} A
H :
  ∀ ⦃B : Type u⦄ [inst : CommRing B] [Small.{w, u} B] [inst_2 : Algebra R B] (I : Ideal B),
    I ^ 2 = ⊥ → Function.Injective (Ideal.Quotient.mkₐ R I).comp
⊢ FormallyUnramified R A

Tactic:
constructor

Goal state after:
case mpr
R : Type v
inst✝³ : CommRing R
A : Type u
inst✝² : CommRing A
inst✝¹ : Algebra R A
inst✝ : Small.{w, u} A
H :
  ∀ ⦃B : Type u⦄ [inst : CommRing B] [Small.{w, u} B] [inst_2 : Algebra R B] (I : Ideal B),
    I ^ 2 = ⊥ → Function.Injective (Ideal.Quotient.mkₐ R I).comp
⊢ Subsingleton Ω[A⁄R]
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
inst✝ : EssFiniteType R S
this : ∀ (t : S ⊗[R] S), (TensorProduct.lmul' R) t = 1 ↔ 1 - t ∈ KaehlerDifferential.ideal R S
⊢ (∃ e, IsIdempotentElem e ∧ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) = S ⊗[R] S ∙ e) ↔
    ∃ t, (∀ (s : S), (1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) * t = 0) ∧ 1 - t ∈ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1)

Tactic:
constructor

Goal state after:
case mp
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
inst✝ : EssFiniteType R S
this : ∀ (t : S ⊗[R] S), (TensorProduct.lmul' R) t = 1 ↔ 1 - t ∈ KaehlerDifferential.ideal R S
⊢ (∃ e, IsIdempotentElem e ∧ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) = S ⊗[R] S ∙ e) →
    ∃ t, (∀ (s : S), (1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) * t = 0) ∧ 1 - t ∈ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1)

case mpr
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
inst✝ : EssFiniteType R S
this : ∀ (t : S ⊗[R] S), (TensorProduct.lmul' R) t = 1 ↔ 1 - t ∈ KaehlerDifferential.ideal R S
⊢ (∃ t, (∀ (s : S), (1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) * t = 0) ∧ 1 - t ∈ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1)) →
    ∃ e, IsIdempotentElem e ∧ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) = S ⊗[R] S ∙ e
Module: Mathlib.RingTheory.Unramified.Finite

Goal state before:
pp: case h
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
inst✝ : EssFiniteType R S
this : ∀ (t : S ⊗[R] S), (TensorProduct.lmul' R) t = 1 ↔ 1 - t ∈ KaehlerDifferential.ideal R S
t e : S ⊗[R] S
ht₁ : ∀ (s : S), (1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) * (1 - e) = 0
ht₂ : e ∈ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1)
⊢ IsIdempotentElem e ∧ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) = S ⊗[R] S ∙ e

Tactic:
constructor

Goal state after:
case h.left
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
inst✝ : EssFiniteType R S
this : ∀ (t : S ⊗[R] S), (TensorProduct.lmul' R) t = 1 ↔ 1 - t ∈ KaehlerDifferential.ideal R S
t e : S ⊗[R] S
ht₁ : ∀ (s : S), (1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) * (1 - e) = 0
ht₂ : e ∈ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1)
⊢ IsIdempotentElem e

case h.right
R : Type u_1
S : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing S
inst✝¹ : Algebra R S
inst✝ : EssFiniteType R S
this : ∀ (t : S ⊗[R] S), (TensorProduct.lmul' R) t = 1 ↔ 1 - t ∈ KaehlerDifferential.ideal R S
t e : S ⊗[R] S
ht₁ : ∀ (s : S), (1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) * (1 - e) = 0
ht₂ : e ∈ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1)
⊢ Ideal.span (Set.range fun s ↦ 1 ⊗ₜ[R] s - s ⊗ₜ[R] 1) = S ⊗[R] S ∙ e
Module: Mathlib.RingTheory.Unramified.Basic

Goal state before:
pp: R : Type u_1
Rₘ : Type u_3
inst✝⁵ : CommRing R
inst✝⁴ : CommRing Rₘ
M : Submonoid R
inst✝³ : Algebra R Rₘ
inst✝² : IsLocalization M Rₘ
Q : Type u_3
inst✝¹ : CommRing Q
inst✝ : Algebra R Q
I : Ideal Q
x✝ : I ^ 2 = ⊥
f₁ f₂ : Rₘ →ₐ[R] Q
a✝ : (Ideal.Quotient.mkₐ R I).comp f₁ = (Ideal.Quotient.mkₐ R I).comp f₂
⊢ (↑f₁).comp (algebraMap R Rₘ) = (↑f₂).comp (algebraMap R Rₘ)

Tactic:
ext

Goal state after:
R : Type u_1
Rₘ : Type u_3
inst✝⁵ : CommRing R
inst✝⁴ : CommRing Rₘ
M : Submonoid R
inst✝³ : Algebra R Rₘ
inst✝² : IsLocalization M Rₘ
Q : Type u_3
inst✝¹ : CommRing Q
inst✝ : Algebra R Q
I : Ideal Q
x✝¹ : I ^ 2 = ⊥
f₁ f₂ : Rₘ →ₐ[R] Q
a✝ : (Ideal.Quotient.mkₐ R I).comp f₁ = (Ideal.Quotient.mkₐ R I).comp f₂
x✝ : R
⊢ ((↑f₁).comp (algebraMap R Rₘ)) x✝ = ((↑f₂).comp (algebraMap R Rₘ)) x✝
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)
⊢ ∑ i ∈ f.support, f i ⊗ₜ[R] (Finsupp.linearCombination R ⇑b) (a i) =
    ∑ k ∈ f.support.biUnion fun i ↦ ((fun i ↦ b.repr (b i * x)) i).support,
      (b.repr (f.sum fun i y ↦ ((fun i ↦ b.repr (b i * x)) i) k • y)).sum fun j c ↦ c • b j ⊗ₜ[R] b k

Tactic:
conv_lhs => simp only [Finsupp.linearCombination, Finsupp.coe_lsum,
    LinearMap.coe_smulRight, LinearMap.id_coe, id_eq, Finsupp.sum, TensorProduct.tmul_sum,
    ← TensorProduct.smul_tmul]

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)
⊢ ∑ i ∈ f.support, ∑ x ∈ (a i).support, ((a i) x • f i) ⊗ₜ[R] b x =
    ∑ k ∈ f.support.biUnion fun i ↦ ((fun i ↦ b.repr (b i * x)) i).support,
      (b.repr (f.sum fun i y ↦ ((fun i ↦ b.repr (b i * x)) 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✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : FormallyUnramified R S
inst✝¹ : EssFiniteType R S
inst✝ : Free R S
I : Type u_2 := Free.ChooseBasisIndex R S
b : Basis I R S := Free.chooseBasis R S
f : I →₀ S
hf : elem R S = f.sum fun i x ↦ x ⊗ₜ[R] b i
⊢ Module.Finite R S

Tactic:
constructor

Goal state after:
R : Type u_1
S : Type u_2
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : FormallyUnramified R S
inst✝¹ : EssFiniteType R S
inst✝ : Free R S
I : Type u_2 := ⋯
b : Basis I R S := ⋯
f : I →₀ S
hf : elem R S = f.sum fun i x ↦ x ⊗ₜ[R] b i
⊢ ⊤.FG
Module: Mathlib.RingTheory.Unramified.Finite

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : FormallyUnramified R S
inst✝¹ : EssFiniteType R S
inst✝ : Free R S
I : Type u_2 := Free.ChooseBasisIndex R S
b : Basis I R S := Free.chooseBasis R S
f : I →₀ S
hf : elem R S = f.sum fun i x ↦ x ⊗ₜ[R] b i
x : S
a : I → I →₀ R := fun i ↦ b.repr (b i * x)
F : I →₀ I →₀ R := Finsupp.onFinset f.support (fun j ↦ b.repr (x * f j)) ⋯
hG : ∀ j ∉ f.support.biUnion fun i ↦ (a i).support, b.repr (f.sum fun i y ↦ (a i) j • y) = 0
G : I →₀ I →₀ R :=
  Finsupp.onFinset (f.support.biUnion fun i ↦ (a i).support) (fun j ↦ b.repr (f.sum fun i y ↦ (a i) j • y)) ⋯
this : (F.sum fun a f ↦ f.sum fun b' c ↦ c • b b' ⊗ₜ[R] b a) = G.sum fun a f ↦ f.sum fun b' c ↦ c • b b' ⊗ₜ[R] b a
⊢ (b.tensorProduct b).repr.symm ((Finsupp.equivCongrLeft (Equiv.prodComm I I)) (Finsupp.curryEquiv.symm F)) =
    (b.tensorProduct b).repr.symm ((Finsupp.equivCongrLeft (Equiv.prodComm I I)) (Finsupp.curryEquiv.symm G))

Tactic:
by
      simpa [Finsupp.linearCombination_apply, Finsupp.sum_uncurry_index]

Goal state after:
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 S
inst✝⁴ : p.IsPrime
inst✝³ : QuasiFiniteAt R p
A : Type u_4
inst✝² : CommRing A
inst✝¹ : Algebra R A
q : Ideal (A ⊗[R] S)
inst✝ : q.IsPrime
hq : p = Ideal.comap TensorProduct.includeRight.toRingHom q
f : A ⊗[R] Localization.AtPrime p →ₐ[A] Localization.AtPrime q :=
  TensorProduct.lift (ofId A (Localization.AtPrime q))
    { toRingHom := Localization.localRingHom p q TensorProduct.includeRight.toRingHom hq, commutes' := ⋯ } ⋯
g : A ⊗[R] S →ₐ[A] A ⊗[R] Localization.AtPrime p :=
  TensorProduct.map (AlgHom.id A A) (IsScalarTower.toAlgHom R S (Localization.AtPrime p))
⊢ f.comp g = IsScalarTower.toAlgHom A (A ⊗[R] S) (Localization.AtPrime q)

Tactic:
ext

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 S
inst✝⁴ : p.IsPrime
inst✝³ : QuasiFiniteAt R p
A : Type u_4
inst✝² : CommRing A
inst✝¹ : Algebra R A
q : Ideal (A ⊗[R] S)
inst✝ : q.IsPrime
hq : p = Ideal.comap TensorProduct.includeRight.toRingHom q
f : A ⊗[R] Localization.AtPrime p →ₐ[A] Localization.AtPrime q :=
  TensorProduct.lift (ofId A (Localization.AtPrime q))
    { toRingHom := Localization.localRingHom p q TensorProduct.includeRight.toRingHom hq, commutes' := ⋯ } ⋯
g : A ⊗[R] S →ₐ[A] A ⊗[R] Localization.AtPrime p :=
  TensorProduct.map (AlgHom.id A A) (IsScalarTower.toAlgHom R S (Localization.AtPrime p))
x✝ : S
⊢ ((AlgHom.restrictScalars R (f.comp g)).comp TensorProduct.includeRight) x✝ =
    ((AlgHom.restrictScalars R (IsScalarTower.toAlgHom A (A ⊗[R] S) (Localization.AtPrime q))).comp
        TensorProduct.includeRight)
      x✝
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
p : Ideal S
inst✝¹ : p.IsPrime
inst✝ : QuasiFiniteAt R p
f : T ≃ₐ[R] S
⊢ p = Ideal.comap (↑f.symm).toRingHom (Ideal.comap f.toRingEquiv.toRingHom p)

Tactic:
ext

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
p : Ideal S
inst✝¹ : p.IsPrime
inst✝ : QuasiFiniteAt R p
f : T ≃ₐ[R] S
x✝ : S
⊢ x✝ ∈ p ↔ x✝ ∈ Ideal.comap (↑f.symm).toRingHom (Ideal.comap f.toRingEquiv.toRingHom p)
Module: Mathlib.RingTheory.Unramified.Finite

Goal state before:
pp: case h
R : Type u_1
S : Type u_2
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : FormallyUnramified R S
inst✝¹ : EssFiniteType R S
inst✝ : Free R S
I : Type u_2 := Free.ChooseBasisIndex R S
b : Basis I R S := Free.chooseBasis R S
f : I →₀ S
hf : elem R S = f.sum fun i x ↦ x ⊗ₜ[R] b i
x : S
a : I → I →₀ R := fun i ↦ b.repr (b i * x)
F : I →₀ I →₀ R := Finsupp.onFinset f.support (fun j ↦ b.repr (x * f j)) ⋯
hG : ∀ j ∉ f.support.biUnion fun i ↦ (a i).support, b.repr (f.sum fun i y ↦ (a i) j • y) = 0
G : I →₀ I →₀ R :=
  Finsupp.onFinset (f.support.biUnion fun i ↦ (a i).support) (fun j ↦ b.repr (f.sum fun i y ↦ (a i) j • y)) ⋯
this : F = G
⊢ x ∈ Submodule.span R ↑(Finset.image₂ (fun i j ↦ f i * b j) f.support f.support)

Tactic:
have : ∀ j, x * f j = f.sum fun i y ↦ a i j • y := by
    intro j
    apply b.repr.injective
    exact DFunLike.congr_fun this j

Goal state after:
case h
R : Type u_1
S : Type u_2
inst✝⁵ : CommRing R
inst✝⁴ : CommRing S
inst✝³ : Algebra R S
inst✝² : FormallyUnramified R S
inst✝¹ : EssFiniteType R S
inst✝ : Free R S
I : Type u_2 := Free.ChooseBasisIndex R S
b : Basis I R S := Free.chooseBasis R S
f : I →₀ S
hf : elem R S = f.sum fun i x ↦ x ⊗ₜ[R] b i
x : S
a : I → I →₀ R := fun i ↦ b.repr (b i * x)
F : I →₀ I →₀ R := Finsupp.onFinset f.support (fun j ↦ b.repr (x * f j)) ⋯
hG : ∀ j ∉ f.support.biUnion fun i ↦ (a i).support, b.repr (f.sum fun i y ↦ (a i) j • y) = 0
G : I →₀ I →₀ R :=
  Finsupp.onFinset (f.support.biUnion fun i ↦ (a i).support) (fun j ↦ b.repr (f.sum fun i y ↦ (a i) j • y)) ⋯
this✝ : F = G
this : ∀ (j : I), x * f j = f.sum fun i y ↦ (a i) j • y
⊢ x ∈ Submodule.span R ↑(Finset.image₂ (fun i j ↦ f i * b j) f.support f.support)
Module: Mathlib.RingTheory.QuasiFinite.Basic

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁹ : CommRing R
inst✝⁸ : CommRing S
inst✝⁷ : Algebra R S
inst✝⁶ : FiniteType R S
p : Ideal R
inst✝⁵ : p.IsPrime
q : Ideal S
inst✝⁴ : q.IsPrime
inst✝³ : q.LiesOver p
inst✝² : QuasiFiniteAt R q
inst✝¹ : Algebra (Localization.AtPrime p) (Localization.AtPrime q)
inst✝ : Localization.AtPrime.IsLiesOverAlgebra p q
q' : Ideal (p.Fiber S) := ((PrimeSpectrum.primesOverOrderIsoFiber R S p) ⟨q, ⋯⟩).asIdeal
hq' : q = Ideal.comap TensorProduct.includeRight.toRingHom q'
this✝ : QuasiFiniteAt p.ResidueField q'
this : q'.IsMaximal
⊢ (Ideal.ResidueField.map q q' TensorProduct.includeRight.toRingHom hq').comp
      ↑(TensorProduct.lift (ofId p.ResidueField q.ResidueField) (IsScalarTower.toAlgHom R S q.ResidueField) ⋯) =
    algebraMap (p.Fiber S) q'.ResidueField

Tactic:
ext

Goal state after:
case h₁
R : Type u_1
S : Type u_2
inst✝⁹ : CommRing R
inst✝⁸ : CommRing S
inst✝⁷ : Algebra R S
inst✝⁶ : FiniteType R S
p : Ideal R
inst✝⁵ : p.IsPrime
q : Ideal S
inst✝⁴ : q.IsPrime
inst✝³ : q.LiesOver p
inst✝² : QuasiFiniteAt R q
inst✝¹ : Algebra (Localization.AtPrime p) (Localization.AtPrime q)
inst✝ : Localization.AtPrime.IsLiesOverAlgebra p q
q' : Ideal (p.Fiber S) := ((PrimeSpectrum.primesOverOrderIsoFiber R S p) ⟨q, ⋯⟩).asIdeal
hq' : q = Ideal.comap TensorProduct.includeRight.toRingHom q'
this✝ : QuasiFiniteAt p.ResidueField q'
this : q'.IsMaximal
x✝ : R
⊢ ((((Ideal.ResidueField.map q q' TensorProduct.includeRight.toRingHom hq').comp
                ↑(TensorProduct.lift (ofId p.ResidueField q.ResidueField) (IsScalarTower.toAlgHom R S q.ResidueField)
                    ⋯)).comp
            TensorProduct.includeLeftRingHom).comp
        (algebraMap R p.ResidueField))
      x✝ =
    (((algebraMap (p.Fiber S) q'.ResidueField).comp TensorProduct.includeLeftRingHom).comp
        (algebraMap R p.ResidueField))
      x✝

case h₂
R : Type u_1
S : Type u_2
inst✝⁹ : CommRing R
inst✝⁸ : CommRing S
inst✝⁷ : Algebra R S
inst✝⁶ : FiniteType R S
p : Ideal R
inst✝⁵ : p.IsPrime
q : Ideal S
inst✝⁴ : q.IsPrime
inst✝³ : q.LiesOver p
inst✝² : QuasiFiniteAt R q
inst✝¹ : Algebra (Localization.AtPrime p) (Localization.AtPrime q)
inst✝ : Localization.AtPrime.IsLiesOverAlgebra p q
q' : Ideal (p.Fiber S) := ((PrimeSpectrum.primesOverOrderIsoFiber R S p) ⟨q, ⋯⟩).asIdeal
hq' : q = Ideal.comap TensorProduct.includeRight.toRingHom q'
this✝ : QuasiFiniteAt p.ResidueField q'
this : q'.IsMaximal
x✝ : S
⊢ (((Ideal.ResidueField.map q q' TensorProduct.includeRight.toRingHom hq').comp
            ↑(TensorProduct.lift (ofId p.ResidueField q.ResidueField) (IsScalarTower.toAlgHom R S q.ResidueField)
                ⋯)).comp
        TensorProduct.includeRight.toRingHom)
      x✝ =
    ((algebraMap (p.Fiber S) q'.ResidueField).comp TensorProduct.includeRight.toRingHom) x✝
Module: Mathlib.RingTheory.Etale.Basic

Goal state before:
pp: R : Type u_2
S : Type u_3
inst✝² : CommRing R
inst✝¹ : CommRing S
inst✝ : Algebra R S
h : Function.Surjective ⇑(algebraMap R S)
⊢ FormallyEtale R S ↔ IsIdempotentElem (RingHom.ker (algebraMap R S))

Tactic:
by
  rw [FormallyEtale.iff_formallyUnramified_and_formallySmooth, ← FormallySmooth.iff_of_surjective h,
    and_iff_right (FormallyUnramified.of_surjective (Algebra.ofId R S) h)]

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

Goal state before:
pp: R : Type u
A : Type v
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
P : Extension R A
inst✝ : FormallySmooth R P.Ring
e : P.ker.Cotangent ≃ₗ[P.Ring] P.Cotangent :=
  let __spread.0 := AddEquiv.refl P.ker.Cotangent;
  { toFun := __spread.0.toFun, map_add' := ⋯, map_smul' := ⋯, invFun := __spread.0.invFun, left_inv := ⋯,
    right_inv := ⋯ }
⊢ (∃ l, l ∘ₗ kerCotangentToTensor R P.Ring A = LinearMap.id) ↔ ∃ l, l ∘ₗ P.cotangentComplex = LinearMap.id

Tactic:
constructor

Goal state after:
case mp
R : Type u
A : Type v
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
P : Extension R A
inst✝ : FormallySmooth R P.Ring
e : P.ker.Cotangent ≃ₗ[P.Ring] P.Cotangent := ⋯
⊢ (∃ l, l ∘ₗ kerCotangentToTensor R P.Ring A = LinearMap.id) → ∃ l, l ∘ₗ P.cotangentComplex = LinearMap.id

case mpr
R : Type u
A : Type v
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
P : Extension R A
inst✝ : FormallySmooth R P.Ring
e : P.ker.Cotangent ≃ₗ[P.Ring] P.Cotangent := ⋯
⊢ (∃ l, l ∘ₗ P.cotangentComplex = LinearMap.id) → ∃ l, l ∘ₗ kerCotangentToTensor R P.Ring A = LinearMap.id
Module: Mathlib.RingTheory.Kaehler.JacobiZariski

Goal state before:
pp: R : Type u₁
S : Type u₂
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
T : Type u₃
inst✝³ : CommRing T
inst✝² : Algebra R T
inst✝¹ : Algebra S T
inst✝ : IsScalarTower R S T
ι : Type w₁
σ : Type w₂
Q : Generators S T ι
P : Generators R S σ
x : (Q.comp P).Ring
hx' : x ∈ (Q.comp P).toExtension.ker
y : (Q.comp P).Ring
hy : y ∈ (Q.comp P).ker * (Q.comp P).ker
e : x - y ∈ Ideal.map (Q.toComp P).toAlgHom P.ker
z : ↥(Q.comp P).ker := ⟨x - y, ⋯⟩
hz : ↑z ∈ Ideal.map (Q.toComp P).toAlgHom.toRingHom P.ker
⊢ Extension.Cotangent.mk ⟨x, hx'⟩ = Extension.Cotangent.mk z

Tactic:
ext

Goal state after:
R : Type u₁
S : Type u₂
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
T : Type u₃
inst✝³ : CommRing T
inst✝² : Algebra R T
inst✝¹ : Algebra S T
inst✝ : IsScalarTower R S T
ι : Type w₁
σ : Type w₂
Q : Generators S T ι
P : Generators R S σ
x : (Q.comp P).Ring
hx' : x ∈ (Q.comp P).toExtension.ker
y : (Q.comp P).Ring
hy : y ∈ (Q.comp P).ker * (Q.comp P).ker
e : x - y ∈ Ideal.map (Q.toComp P).toAlgHom P.ker
z : ↥(Q.comp P).ker := ⋯
hz : ↑z ∈ Ideal.map (Q.toComp P).toAlgHom.toRingHom P.ker
⊢ (Extension.Cotangent.mk ⟨x, hx'⟩).val = (Extension.Cotangent.mk z).val
Module: Mathlib.RingTheory.Smooth.Basic

Goal state before:
pp: R : Type u
A : Type v
inst✝⁵ : CommRing R
inst✝⁴ : CommRing A
inst✝³ : Algebra R A
P : Type u_2
inst✝² : CommRing P
inst✝¹ : Algebra R P
inst✝ : FormallySmooth R P
f : P →ₐ[R] A
hf : Function.Surjective ⇑f
this : Algebra P A := f.toAlgebra
⊢ Nonempty { l // l ∘ₗ kerCotangentToTensor R P A = LinearMap.id } ↔
    Nonempty { g // f.kerSquareLift.comp g = AlgHom.id R A }

Tactic:
(retractionKerCotangentToTensorEquivSection hf).nonempty_congr

Goal state after:
R : Type u
A : Type v
inst✝⁵ : CommRing R
inst✝⁴ : CommRing A
inst✝³ : Algebra R A
P : Type u_2
inst✝² : CommRing P
inst✝¹ : Algebra R P
inst✝ : FormallySmooth R P
f : P →ₐ[R] A
hf : Function.Surjective ⇑f
this : Algebra P A := f.toAlgebra
⊢ Nonempty { g // (IsScalarTower.toAlgHom R P A).kerSquareLift.comp g = AlgHom.id R A } ↔
    Nonempty { g // f.kerSquareLift.comp g = AlgHom.id R A }
Module: Mathlib.RingTheory.Smooth.Basic

Goal state before:
pp: R : Type u_4
inst✝² : CommRing R
A : Type u_6
inst✝¹ : CommRing A
inst✝ : Algebra R A
h : Function.Surjective ⇑(algebraMap R A)
⊢ (∃ g, (ofId R A).kerSquareLift.comp g = AlgHom.id R A) ↔ IsIdempotentElem (RingHom.ker (algebraMap R A))

Tactic:
constructor

Goal state after:
case mp
R : Type u_4
inst✝² : CommRing R
A : Type u_6
inst✝¹ : CommRing A
inst✝ : Algebra R A
h : Function.Surjective ⇑(algebraMap R A)
⊢ (∃ g, (ofId R A).kerSquareLift.comp g = AlgHom.id R A) → IsIdempotentElem (RingHom.ker (algebraMap R A))

case mpr
R : Type u_4
inst✝² : CommRing R
A : Type u_6
inst✝¹ : CommRing A
inst✝ : Algebra R A
h : Function.Surjective ⇑(algebraMap R A)
⊢ IsIdempotentElem (RingHom.ker (algebraMap R A)) → ∃ g, (ofId R A).kerSquareLift.comp g = AlgHom.id R A
Module: Mathlib.RingTheory.Smooth.Basic

Goal state before:
pp: R : Type u_4
inst✝² : CommRing R
A : Type u_6
inst✝¹ : CommRing A
inst✝ : Algebra R A
h : Function.Surjective ⇑(algebraMap R A)
g : A →ₐ[R] R ⧸ RingHom.ker (ofId R A).toRingHom ^ 2
hg : (ofId R A).kerSquareLift.comp g = AlgHom.id R A
⊢ (g.comp (ofId R A).kerSquareLift).comp (Ideal.Quotient.mkₐ R (RingHom.ker (algebraMap R A) ^ 2)) =
    (AlgHom.id R (R ⧸ RingHom.ker (algebraMap R A) ^ 2)).comp (Ideal.Quotient.mkₐ R (RingHom.ker (algebraMap R A) ^ 2))

Tactic:
ext

Goal state after:
Module: Mathlib.RingTheory.Kaehler.JacobiZariski

Goal state before:
pp: R : Type u₁
S : Type u₂
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
T : Type u₃
inst✝³ : CommRing T
inst✝² : Algebra R T
inst✝¹ : Algebra S T
inst✝ : IsScalarTower R S T
ι : Type w₁
Q : Generators S T ι
i : ι
⊢ (δAux R Q) (X i) = 0

Tactic:
rw [X, δAux_monomial]

Goal state after:
R : Type u₁
S : Type u₂
inst✝⁶ : CommRing R
inst✝⁵ : CommRing S
inst✝⁴ : Algebra R S
T : Type u₃
inst✝³ : CommRing T
inst✝² : Algebra R T
inst✝¹ : Algebra S T
inst✝ : IsScalarTower R S T
ι : Type w₁
Q : Generators S T ι
i : ι
⊢ ((Finsupp.single i 1).prod fun x1 x2 ↦ Q.val x1 ^ x2) ⊗ₜ[S] (D R S) 1 = 0
Module: Mathlib.RingTheory.Smooth.Basic

Goal state before:
pp: case h
R : Type u_4
Rₘ : Type u_6
inst✝³ : CommRing R
inst✝² : CommRing Rₘ
M : Submonoid R
inst✝¹ : Algebra R Rₘ
inst✝ : IsLocalization M Rₘ
Q : Type (max u_4 u_6)
x✝¹ : CommRing Q
x✝ : Algebra R Q
I : Ideal Q
e : I ^ 2 = ⊥
f : Rₘ →ₐ[R] Q ⧸ I
this✝ : ∀ (x : ↥M), IsUnit ((algebraMap R Q) ↑x)
this : Rₘ →ₐ[R] Q :=
  let __src := IsLocalization.lift this✝;
  { toRingHom := __src, commutes' := ⋯ }
⊢ (↑((Ideal.Quotient.mkₐ R I).comp this)).comp (algebraMap R Rₘ) = (↑f).comp (algebraMap R Rₘ)

Tactic:
ext

Goal state after:
case h
R : Type u_4
Rₘ : Type u_6
inst✝³ : CommRing R
inst✝² : CommRing Rₘ
M : Submonoid R
inst✝¹ : Algebra R Rₘ
inst✝ : IsLocalization M Rₘ
Q : Type (max u_4 u_6)
x✝² : CommRing Q
x✝¹ : Algebra R Q
I : Ideal Q
e : I ^ 2 = ⊥
f : Rₘ →ₐ[R] Q ⧸ I
this✝ : ∀ (x : ↥M), IsUnit ((algebraMap R Q) ↑x)
this : Rₘ →ₐ[R] Q :=
  let __src := IsLocalization.lift this✝;
  { toRingHom := __src, commutes' := ⋯ }
x✝ : R
⊢ ((↑((Ideal.Quotient.mkₐ R I).comp this)).comp (algebraMap R Rₘ)) x✝ = ((↑f).comp (algebraMap R Rₘ)) x✝
Module: Mathlib.RingTheory.Smooth.Basic

Goal state before:
pp: case h
R : Type u_4
Rₘ : Type u_6
Sₘ : Type u_7
inst✝⁸ : CommRing R
inst✝⁷ : CommRing Rₘ
inst✝⁶ : CommRing Sₘ
M : Submonoid R
inst✝⁵ : Algebra R Sₘ
inst✝⁴ : Algebra R Rₘ
inst✝³ : Algebra Rₘ Sₘ
inst✝² : IsScalarTower R Rₘ Sₘ
inst✝¹ : IsLocalization M Rₘ
inst✝ : FormallySmooth R Sₘ
Q : Type (max u_6 u_7)
x✝¹ : CommRing Q
x✝ : Algebra Rₘ Q
I : Ideal Q
e : I ^ 2 = ⊥
f✝ : Sₘ →ₐ[Rₘ] Q ⧸ I
this✝ : Algebra R Q := ⋯
this : IsScalarTower R Rₘ Q := ⋯
f : Sₘ →ₐ[Rₘ] Q := ⋯
⊢ (Ideal.Quotient.mkₐ Rₘ I).comp f = f✝

Tactic:
ext

Goal state after:
case h
R : Type u_4
Rₘ : Type u_6
Sₘ : Type u_7
inst✝⁸ : CommRing R
inst✝⁷ : CommRing Rₘ
inst✝⁶ : CommRing Sₘ
M : Submonoid R
inst✝⁵ : Algebra R Sₘ
inst✝⁴ : Algebra R Rₘ
inst✝³ : Algebra Rₘ Sₘ
inst✝² : IsScalarTower R Rₘ Sₘ
inst✝¹ : IsLocalization M Rₘ
inst✝ : FormallySmooth R Sₘ
Q : Type (max u_6 u_7)
x✝² : CommRing Q
x✝¹ : Algebra Rₘ Q
I : Ideal Q
e : I ^ 2 = ⊥
f✝ : Sₘ →ₐ[Rₘ] Q ⧸ I
this✝ : Algebra R Q := ((algebraMap Rₘ Q).comp (algebraMap R Rₘ)).toAlgebra
this : IsScalarTower R Rₘ Q := IsScalarTower.of_algebraMap_eq' rfl
f : Sₘ →ₐ[Rₘ] Q :=
  let __src := lift I ⋯ (AlgHom.restrictScalars R f✝);
  { toRingHom := __src.toRingHom, commutes' := ⋯ }
x✝ : Sₘ
⊢ ((Ideal.Quotient.mkₐ Rₘ I).comp f) x✝ = f✝ x✝