Module

SubalgebraPrime.lean

Nyll.SchemeTheory.RingTheory.Localization.SubalgebraPrime
13 declarations indexed from sourceView source ↗

Native subalgebra-prime localization maps with closed coefficient squares

The ring objects are the actual native prime localizations. Their coefficient maps are the native algebra maps, retained as RingHoms. The localization map is Localization.localRingHom; its native coefficient equation is proved in the ring-only scope before specializing to a subalgebra.

The subalgebra base maps are the literal composites of these coefficient maps with the original algebra maps. Their proved square mentions only the computed RingHoms. No comparison, localization compatibility, alternate algebra dictionary, or independent local model is assumed.

Imports8
  • Mathlib.Algebra.Algebra.Hom
  • Mathlib.Algebra.Algebra.Subalgebra.Basic
  • Mathlib.Algebra.Category.Ring.Basic
  • Mathlib.Algebra.Category.CommAlgCat.Basic
  • Mathlib.Algebra.Algebra.Tower
  • Mathlib.Algebra.Ring.Hom.Defs
  • Mathlib.RingTheory.Ideal.Maps
  • Mathlib.RingTheory.Localization.AtPrime.Basic
Imported by5

Declarations

SchemeTheory.primeLocalizationCommRingCat

The actual native prime localization, bundled with its native ring.

Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
def primeLocalizationCommRingCat (C : Type v) [CommRing C]
    (Q : Ideal C) [Q.IsPrime] : CommRingCat.{v}
SchemeTheory.primeLocalizationComapCommRingCat

The actual native localization at the contracted prime. The comap-prime proof is constructed here, rather than requested from a caller.

Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
def primeLocalizationComapCommRingCat
    {R : Type u} {C : Type v} [CommRing R] [CommRing C]
    (f : R →+* C) (Q : Ideal C) [Q.IsPrime] : CommRingCat.{u}
SchemeTheory.primeLocalizationCoefficientMap

The native coefficient map into the actual prime localization.

Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
def primeLocalizationCoefficientMap (C : Type v) [CommRing C]
    (Q : Ideal C) [Q.IsPrime] : C →+* primeLocalizationCommRingCat C Q
SchemeTheory.primeLocalizationComapCoefficientMap

The native coefficient map into the actual contracted-prime localization.

Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
def primeLocalizationComapCoefficientMap
    {R : Type u} {C : Type v} [CommRing R] [CommRing C]
    (f : R →+* C) (Q : Ideal C) [Q.IsPrime] :
    R →+* primeLocalizationComapCommRingCat f Q
SchemeTheory.primeLocalizationComapMap

The actual map between the native prime localizations.

Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
def primeLocalizationComapMap
    {R : Type u} {C : Type v} [CommRing R] [CommRing C]
    (f : R →+* C) (Q : Ideal C) [Q.IsPrime] :
    primeLocalizationComapCommRingCat f Q →+* primeLocalizationCommRingCat C Q
SchemeTheory.primeLocalizationComapMap_comp_coefficient

The native localization coefficient equation, with both coefficient maps retained as the actual constructed RingHoms in its public statement.

Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
theorem primeLocalizationComapMap_comp_coefficient
    {R : Type u} {C : Type v} [CommRing R] [CommRing C]
    (f : R →+* C) (Q : Ideal C) [Q.IsPrime] :
    (primeLocalizationComapMap f Q).comp (primeLocalizationComapCoefficientMap f Q) =
      (primeLocalizationCoefficientMap C Q).comp f
SchemeTheory.primeLocalizationBaseMap

The original base-ring map into the actual ambient prime localization.

Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
def primeLocalizationBaseMap (A : Type u) (C : Type v)
    [CommRing A] [CommRing C] [Algebra A C]
    (Q : Ideal C) [Q.IsPrime] : A →+* primeLocalizationCommRingCat C Q
SchemeTheory.subalgebraPrimeLocalizationSource

The source is exactly the native localization of the actual subalgebra at the contraction of the original prime.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
variable {A : Type u} {C : Type v} [CommRing A] [CommRing C] [Algebra A C]
def subalgebraPrimeLocalizationSource (S : Subalgebra A C)
    (Q : Ideal C) [Q.IsPrime] : CommRingCat.{v}
SchemeTheory.subalgebraPrimeLocalizationMap

The literal localized inclusion of the actual subalgebra.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
variable {A : Type u} {C : Type v} [CommRing A] [CommRing C] [Algebra A C]
def subalgebraPrimeLocalizationMap (S : Subalgebra A C)
    (Q : Ideal C) [Q.IsPrime] :
    subalgebraPrimeLocalizationSource S Q →+* primeLocalizationCommRingCat C Q
SchemeTheory.subalgebraPrimeLocalizationBaseMap

The original base-ring map into the actual subalgebra localization.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
variable {A : Type u} {C : Type v} [CommRing A] [CommRing C] [Algebra A C]
def subalgebraPrimeLocalizationBaseMap (S : Subalgebra A C)
    (Q : Ideal C) [Q.IsPrime] : A →+* subalgebraPrimeLocalizationSource S Q
SchemeTheory.subalgebraPrimeLocalizationMap_comp_base

The literal subalgebra localization map preserves the original base map. Its public equation contains only the computed native RingHoms.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
variable {A : Type u} {C : Type v} [CommRing A] [CommRing C] [Algebra A C]
theorem subalgebraPrimeLocalizationMap_comp_base
    (S : Subalgebra A C) (Q : Ideal C) [Q.IsPrime] :
    (subalgebraPrimeLocalizationMap S Q).comp (subalgebraPrimeLocalizationBaseMap S Q) =
      primeLocalizationBaseMap A C Q
SchemeTheory.subalgebraPrimeLocalizationAlgebra

The same actual source localization with its native coefficient algebra. No alternate algebra action is installed.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
variable {A : Type u} {C : Type v} [CommRing A] [CommRing C] [Algebra A C]
def subalgebraPrimeLocalizationAlgebra (S : Subalgebra A C)
    (Q : Ideal C) [Q.IsPrime] : CommAlgCat.{v} A
SchemeTheory.subalgebraPrimeLocalizationBaseMap_eq_algebraMap

The computed coefficient composite is the native base-algebra map on that exact localization, by the existing native scalar tower.

Source context 4 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace SchemeTheory
universe u v
variable {A : Type u} {C : Type v} [CommRing A] [CommRing C] [Algebra A C]
theorem subalgebraPrimeLocalizationBaseMap_eq_algebraMap
    (S : Subalgebra A C) (Q : Ideal C) [Q.IsPrime] :
    (subalgebraPrimeLocalizationBaseMap S Q :
        A →+* subalgebraPrimeLocalizationAlgebra S Q) =
      algebraMap A (subalgebraPrimeLocalizationAlgebra S Q)