-- Mathlib/RingTheory/Trace/Quotient.lean
/-- The trace map on `B → A` coincides with the trace map on `B⧸pB → A⧸p`. -/
lemma Algebra.trace_quotient_eq_of_isDedekindDomain (x) [IsDedekindDomain R] [IsDomain S]
    [NoZeroSMulDivisors R S] [Module.Finite R S] [IsIntegrallyClosed S] :
    Algebra.trace (R ⧸ p) (S ⧸ pS) (Ideal.Quotient.mk pS x) =
      Ideal.Quotient.mk p (Algebra.intTrace R S x)

Proof state:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this✝⁴ : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
this✝³ : IsScalarTower R Rₚ Sₚ
this✝² : IsLocalization (Submonoid.map (algebraMap R S) p.primeCompl) Sₚ
e : algebraMapSubmonoid S p.primeCompl ≤ S⁰
this✝¹ : IsDomain Sₚ
this✝ : NoZeroSMulDivisors Rₚ Sₚ
this : Module.Finite Rₚ Sₚ
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Tactic:
haveI : IsIntegrallyClosed Sₚ := isIntegrallyClosed_of_isLocalization _ _ e

Result:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this✝⁵ : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
this✝⁴ : IsScalarTower R Rₚ Sₚ
this✝³ : IsLocalization (Submonoid.map (algebraMap R S) p.primeCompl) Sₚ
e : algebraMapSubmonoid S p.primeCompl ≤ S⁰
this✝² : IsDomain Sₚ
this✝¹ : NoZeroSMulDivisors Rₚ Sₚ
this✝ : Module.Finite Rₚ Sₚ
this : IsIntegrallyClosed Sₚ
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Proof state:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Tactic:
let Sₚ := Localization (Algebra.algebraMapSubmonoid S p.primeCompl)

Result:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Proof state:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this✝ : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
this : IsScalarTower R Rₚ Sₚ
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Tactic:
haveI : IsLocalization (Submonoid.map (algebraMap R S) (Ideal.primeCompl p)) Sₚ :=
  inferInstanceAs (IsLocalization (Algebra.algebraMapSubmonoid S p.primeCompl) Sₚ)

Result:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this✝¹ : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
this✝ : IsScalarTower R Rₚ Sₚ
this : IsLocalization (Submonoid.map (algebraMap R S) p.primeCompl) Sₚ
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Proof state:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this✝³ : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
this✝² : IsScalarTower R Rₚ Sₚ
this✝¹ : IsLocalization (Submonoid.map (algebraMap R S) p.primeCompl) Sₚ
e : algebraMapSubmonoid S p.primeCompl ≤ S⁰
this✝ : IsDomain Sₚ
this : NoZeroSMulDivisors Rₚ Sₚ
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Tactic:
haveI : Module.Finite Rₚ Sₚ := Module.Finite_of_isLocalization R S _ _ p.primeCompl

Result:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this✝⁴ : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
this✝³ : IsScalarTower R Rₚ Sₚ
this✝² : IsLocalization (Submonoid.map (algebraMap R S) p.primeCompl) Sₚ
e : algebraMapSubmonoid S p.primeCompl ≤ S⁰
this✝¹ : IsDomain Sₚ
this✝ : NoZeroSMulDivisors Rₚ Sₚ
this : Module.Finite Rₚ Sₚ
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Proof state:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)

Tactic:
haveI : IsScalarTower R Rₚ Sₚ := IsScalarTower.of_algebraMap_eq'
  (by rw [RingHom.algebraMap_toAlgebra, IsLocalization.map_comp, ← IsScalarTower.algebraMap_eq])

Result:
R : Type u_1
S : Type u_2
inst✝⁸ : CommRing R
inst✝⁷ : CommRing S
inst✝⁶ : Algebra R S
p : Ideal R
inst✝⁵ : p.IsMaximal
x : S
inst✝⁴ : IsDedekindDomain R
inst✝³ : IsDomain S
inst✝² : NoZeroSMulDivisors R S
inst✝¹ : Module.Finite R S
inst✝ : IsIntegrallyClosed S
Rₚ : Type u_1 := Localization.AtPrime p
Sₚ : Type u_2 := Localization (algebraMapSubmonoid S p.primeCompl)
this✝ : Algebra Rₚ Sₚ := localizationAlgebra p.primeCompl S
this : IsScalarTower R Rₚ Sₚ
⊢ (trace (R ⧸ p) (S ⧸ pS)) ((Ideal.Quotient.mk pS) x) = (Ideal.Quotient.mk p) ((intTrace R S) x)