mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.RingTheory.Smooth.Kaehler

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
l : S ⊗[P] Ω[P⁄R] →ₗ[P] ↥(RingHom.ker (algebraMap P S))
hl : l ∘ₗ kerToTensor R P S = LinearMap.id
σ : S → P
hσ : ∀ (x : S), (algebraMap P S) (σ x) = x
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
r : R
⊢ σ ((algebraMap R S) r) - ↑(l (1 ⊗ₜ[P] (D R P) (σ ((algebraMap R S) r)))) = (algebraMap R P) r

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
l : S ⊗[P] Ω[P⁄R] →ₗ[P] ↥(RingHom.ker (algebraMap P S))
hl : l ∘ₗ kerToTensor R P S = LinearMap.id
σ : S → P
hσ : ∀ (x : S), (algebraMap P S) (σ x) = x
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
x : P
⊢ (algebraMap P S) (σ ((algebraMap P S) x)) = (algebraMap P S) x

Tactic:
by

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
σ : Type w₂
Q : Generators S T ι
P : Generators R S σ
⊢ Function.Exact ⇑(δ Q P) ⇑(mapBaseChange R S T)

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝¹ : Module.Finite K A
this✝ : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
r : A
s : K
this : s • (Ideal.Quotient.mk (IsLocalRing.maximalIdeal A)) r = r • e s
⊢ (↑K ((ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ e'.toLinearMap)) (r ⊗ₜ[K] e s) =
    (↑K
        (TensorProduct.AlgebraTensorModule.lift
          (↑K (lsmul A A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap.flip).flip))
      (r ⊗ₜ[K] e s)

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
l : S ⊗[P] Ω[P⁄R] →ₗ[P] ↥(RingHom.ker (algebraMap P S))
hl : l ∘ₗ kerToTensor R P S = LinearMap.id
σ : S → P
hσ : ∀ (x : S), (algebraMap P S) (σ x) = x
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
⊢ (IsScalarTower.toAlgHom R P S).comp (sectionOfRetractionKerToTensorAux l hl σ hσ hf') = AlgHom.id R S

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
⊢ (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
l : { l // l ∘ₗ kerToTensor R P S = LinearMap.id }
p s : P
x y : S ⊗[P] Ω[P⁄R]
⊢ ↑(↑l x) * ↑(↑l y) = 0

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
hf : (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id
⊢ f 1 • 1 = 1

Tactic:
by

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
σ : Type w₂
Q : Generators S T ι
P : Generators R S σ
x : Q.toExtension.H1Cotangent
y : (Q.comp P).toExtension.Cotangent
hy : (Extension.Cotangent.map (Q.ofComp P).toExtensionHom) y = ↑x
z : T ⊗[S] P.toExtension.CotangentSpace
hz :
  (LinearMap.liftBaseChange T (Extension.CotangentSpace.map (Q.toComp P).toExtensionHom)) z =
    (Q.comp P).toExtension.cotangentComplex y
⊢ (δ Q P) x = (LinearMap.baseChange T P.toExtension.toKaehler) z

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
l : { l // l ∘ₗ kerToTensor R P S = LinearMap.id }
⊢ (fun g ↦ ⟨retractionOfSectionOfKerSqZero (↑g) hf' ⋯, ⋯⟩)
      ((fun l ↦ ⟨sectionOfRetractionKerToTensor ↑l ⋯ hf' hf, ⋯⟩) l) =
    l

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
g : { g // (IsScalarTower.toAlgHom R P S).comp g = AlgHom.id R S }
⊢ (fun l ↦ ⟨sectionOfRetractionKerToTensor ↑l ⋯ hf' hf, ⋯⟩)
      ((fun g ↦ ⟨retractionOfSectionOfKerSqZero (↑g) hf' ⋯, ⋯⟩) g) =
    g

Tactic:
by

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
σ : Type w₂
Q : Generators S T ι
P : Generators R S σ
x : ↥Q.ker
hx : Extension.Cotangent.mk x ∈ Q.toExtension.cotangentComplex.ker
y : (Q.comp P).toExtension.Cotangent := Extension.Cotangent.mk (Q.kerCompPreimage P x)
⊢ (Extension.Cotangent.map (Q.ofComp P).toExtensionHom) y = Extension.Cotangent.mk x

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
hf : (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id
hf₁ : f 1 • 1 = 1
⊢ 1 - f 1 ∈ IsLocalRing.maximalIdeal A

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
hf : (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id
hf₁ : f 1 • 1 = 1
hf₂ : 1 - f 1 ∈ IsLocalRing.maximalIdeal A
⊢ IsIdempotentElem (1 - f 1)

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
⊢ Derivation R (P ⧸ RingHom.ker (algebraMap P S) ^ 2) (S ⊗[P] Ω[P⁄R])

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
f₁ : Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] →ₗ[P ⧸ RingHom.ker (algebraMap P S) ^ 2] S ⊗[P] Ω[P⁄R] :=
  (derivationQuotKerSq R P S).liftKaehlerDifferential
f₂ : S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] →ₗ[S] S ⊗[P] Ω[P⁄R] :=
  AlgebraTensorModule.lift
    ((LinearMap.ringLmapEquivSelf S S
          (Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] →ₗ[P ⧸ RingHom.ker (algebraMap P S) ^ 2] S ⊗[P] Ω[P⁄R])).symm
      f₁)
f₃ : Ω[P⁄R] →ₗ[P] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] :=
  KaehlerDifferential.map R R P (P ⧸ RingHom.ker (algebraMap P S) ^ 2)
f₄ : Ω[P⁄R] →ₗ[P] S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] :=
  ↑P ((mk (P ⧸ RingHom.ker (algebraMap P S) ^ 2) S Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R]) 1) ∘ₗ f₃
f₅ : S ⊗[P] Ω[P⁄R] →ₗ[S] S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] :=
  AlgebraTensorModule.lift
    ((LinearMap.ringLmapEquivSelf S S
          (Ω[P⁄R] →ₗ[P] S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R])).symm
      f₄)
⊢ Function.LeftInverse (⇑f₅) f₂.toFun

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
hf : (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id
hf₁ : f 1 • 1 = 1
hf₂ : 1 - f 1 ∈ IsLocalRing.maximalIdeal A
hf₃ : IsIdempotentElem (1 - f 1)
n : ℕ
hn : IsLocalRing.maximalIdeal A ^ n = 0
⊢ (1 - f 1) ^ n = 0

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
f₁ : Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] →ₗ[P ⧸ RingHom.ker (algebraMap P S) ^ 2] S ⊗[P] Ω[P⁄R] :=
  (derivationQuotKerSq R P S).liftKaehlerDifferential
f₂ : S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] →ₗ[S] S ⊗[P] Ω[P⁄R] :=
  AlgebraTensorModule.lift
    ((LinearMap.ringLmapEquivSelf S S
          (Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] →ₗ[P ⧸ RingHom.ker (algebraMap P S) ^ 2] S ⊗[P] Ω[P⁄R])).symm
      f₁)
f₃ : Ω[P⁄R] →ₗ[P] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] :=
  KaehlerDifferential.map R R P (P ⧸ RingHom.ker (algebraMap P S) ^ 2)
f₄ : Ω[P⁄R] →ₗ[P] S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] :=
  ↑P ((mk (P ⧸ RingHom.ker (algebraMap P S) ^ 2) S Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R]) 1) ∘ₗ f₃
f₅ : S ⊗[P] Ω[P⁄R] →ₗ[S] S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R] :=
  AlgebraTensorModule.lift
    ((LinearMap.ringLmapEquivSelf S S
          (Ω[P⁄R] →ₗ[P] S ⊗[P ⧸ RingHom.ker (algebraMap P S) ^ 2] Ω[P ⧸ RingHom.ker (algebraMap P S) ^ 2⁄R])).symm
      f₄)
⊢ Function.RightInverse (⇑f₅) f₂.toFun

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
s : S
t : P
⊢ (tensorKaehlerQuotKerSqEquiv R P S)
      (s ⊗ₜ[P ⧸ RingHom.ker (algebraMap P S) ^ 2]
        (D R (P ⧸ RingHom.ker (algebraMap P S) ^ 2)) ((Ideal.Quotient.mk (RingHom.ker (algebraMap P S) ^ 2)) t)) =
    s ⊗ₜ[P] (D R P) t

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
s : S
t : P
⊢ (tensorKaehlerQuotKerSqEquiv R P S).symm (s ⊗ₜ[P] (D R P) t) =
    s ⊗ₜ[P ⧸ RingHom.ker (algebraMap P S) ^ 2]
      (D R (P ⧸ RingHom.ker (algebraMap P S) ^ 2)) ((Ideal.Quotient.mk (RingHom.ker (algebraMap P S) ^ 2)) t)

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
P' : Type u_2 := P ⧸ RingHom.ker (algebraMap P S) ^ 2
h₁ : Surjective ⇑(algebraMap P' S)
⊢ RingHom.ker (algebraMap P' S) ^ 2 = ⊥

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
hf : (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id
hf₁ : f 1 • 1 = 1
hf₂ : 1 - f 1 ∈ IsLocalRing.maximalIdeal A
hf₃ : IsIdempotentElem (1 - f 1)
⊢ f 1 = 1

Tactic:
by

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

Goal state before:
pp: R : Type u_1
P : Type u_2
S : Type u_3
inst✝⁶ : CommRing R
inst✝⁵ : CommRing P
inst✝⁴ : CommRing S
inst✝³ : Algebra R P
inst✝² : Algebra P S
inst✝¹ : Algebra R S
inst✝ : IsScalarTower R P S
hf' : RingHom.ker (algebraMap P S) ^ 2 = ⊥
hf : Surjective ⇑(algebraMap P S)
P' : Type u_2 := P ⧸ RingHom.ker (algebraMap P S) ^ 2
h₁ : Surjective ⇑(algebraMap P' S)
h₂ : RingHom.ker (algebraMap P' S) ^ 2 = ⊥
e₁ : (RingHom.ker (algebraMap P S)).Cotangent ≃ₗ[P] ↥(RingHom.ker (algebraMap P' S)) :=
  (RingHom.ker (algebraMap P S)).cotangentEquivIdeal ≪≫ₗ
    LinearEquiv.restrictScalars P
      (LinearEquiv.ofEq (RingHom.ker (IsScalarTower.toAlgHom R P S).toRingHom).cotangentIdeal
        (RingHom.ker (IsScalarTower.toAlgHom R P S).kerSquareLift.toRingHom) ⋯)
e₂ : S ⊗[P'] Ω[P'⁄R] ≃ₗ[P] S ⊗[P] Ω[P⁄R] := LinearEquiv.restrictScalars P (tensorKaehlerQuotKerSqEquiv R P S)
⊢ kerCotangentToTensor R P S = ↑e₂ ∘ₗ ↑P (kerToTensor R P' S) ∘ₗ ↑e₁

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
hf : (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id
hf₁ : f 1 • 1 = 1
hf₂ : 1 - f 1 ∈ IsLocalRing.maximalIdeal A
hf₃ : IsIdempotentElem (1 - f 1)
hf₄ : f 1 = 1
x : K
⊢ (⇑e.symm ∘ ⇑(algebraMap A (A ⧸ IsLocalRing.maximalIdeal A))) ((algebraMap K A) x) = x

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
this✝ : Module.Finite K A
this : IsArtinianRing A
hA : IsNilpotent (IsLocalRing.maximalIdeal A)
e : K ≃ₐ[K] A ⧸ IsLocalRing.maximalIdeal A :=
  let __spread.0 := ofId K (A ⧸ IsLocalRing.maximalIdeal A);
  let __spread.1 := Equiv.ofBijective ⇑(algebraMap K (A ⧸ IsLocalRing.maximalIdeal A)) ⋯;
  { toFun := (↑↑__spread.0.toRingHom).toFun, invFun := __spread.1.invFun, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯,
    map_add' := ⋯, commutes' := ⋯ }
e' : A ⊗[K] (A ⧸ IsLocalRing.maximalIdeal A) ≃ₐ[A] A :=
  (TensorProduct.congr AlgEquiv.refl e.symm).trans (TensorProduct.rid K A A)
f : A ⧸ IsLocalRing.maximalIdeal A →ₗ[A] A := e'.toLinearMap ∘ₗ sec K A (A ⧸ IsLocalRing.maximalIdeal A)
hf : (ofId A (A ⧸ IsLocalRing.maximalIdeal A)).toLinearMap ∘ₗ f = LinearMap.id
hf₁ : f 1 • 1 = 1
hf₂ : 1 - f 1 ∈ IsLocalRing.maximalIdeal A
hf₃ : IsIdempotentElem (1 - f 1)
hf₄ : f 1 = 1
x : A
⊢ ⇑(algebraMap K A) = ⇑f ∘ ⇑e

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
⊢ Function.Bijective ⇑(algebraMap K A)

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁶ : Field K
inst✝⁵ : CommRing A
inst✝⁴ : Algebra K A
inst✝³ : FormallyUnramified K A
inst✝² : EssFiniteType K A
inst✝¹ : IsAlgClosed K
inst✝ : IsLocalRing A
⊢ IsField A

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁴ : Field K
inst✝³ : CommRing A
inst✝² : Algebra K A
inst✝¹ : FormallyUnramified K A
inst✝ : EssFiniteType K A
x : A
hx : IsNilpotent x
f : A →ₐ[K] AlgebraicClosure K ⊗[K] A := TensorProduct.includeRight
⊢ ⇑f = ⇑(LinearMap.rTensor A (ofId K (AlgebraicClosure K)).toLinearMap ∘ₗ (TensorProduct.lid K A).symm.toLinearMap)

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁴ : Field K
inst✝³ : CommRing A
inst✝² : Algebra K A
inst✝¹ : FormallyUnramified K A
inst✝ : EssFiniteType K A
x : A
hx : IsNilpotent x
f : A →ₐ[K] AlgebraicClosure K ⊗[K] A := TensorProduct.includeRight
this✝ :
  ⇑f = ⇑(LinearMap.rTensor A (ofId K (AlgebraicClosure K)).toLinearMap ∘ₗ (TensorProduct.lid K A).symm.toLinearMap)
this : Function.Injective ⇑(LinearMap.rTensor A (ofId K (AlgebraicClosure K)).toLinearMap)
⊢ Function.Injective
    ⇑(LinearMap.rTensor A (ofId K (AlgebraicClosure K)).toLinearMap ∘ₗ (TensorProduct.lid K A).symm.toLinearMap)

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁴ : Field K
inst✝³ : CommRing A
inst✝² : Algebra K A
inst✝¹ : FormallyUnramified K A
inst✝ : EssFiniteType K A
x : A
hx : IsNilpotent x
f : A →ₐ[K] AlgebraicClosure K ⊗[K] A := TensorProduct.includeRight
⊢ Function.Injective ⇑f

Tactic:
by

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

Goal state before:
pp: K : Type u_1
A : Type u_2
inst✝⁴ : Field K
inst✝³ : CommRing A
inst✝² : Algebra K A
inst✝¹ : FormallyUnramified K A
inst✝ : EssFiniteType K A
⊢ IsReduced A

Tactic:
by

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

Goal state before:
pp: A : Type u_2
inst✝⁵ : CommRing A
B : Type u_4
inst✝⁴ : CommRing B
inst✝³ : Algebra A B
inst✝² : EssFiniteType A B
inst✝¹ : FormallyUnramified A B
p : Ideal A
inst✝ : p.IsMaximal
⊢ (Ideal.map (algebraMap A B) p).IsRadical

Tactic:
by

Goal state after: