Module

CommAlgRingMap.lean

Nyll.SchemeTheory.CategoryTheory.CommAlgRingMap
5 declarations indexed from sourceView source ↗

Native categorical algebra maps from their proved coefficient squares

The coefficient maps are the native maps stored by the commutative algebra objects. The categorical morphism is constructed only after its actual RingHom coefficient square has been proved. No new algebra action is used.

Declarations

SchemeTheory.commAlgCoefficientMap

The coefficient map of the actual native commutative algebra object.

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} [CommRing A]
def commAlgCoefficientMap (R : CommAlgCat.{v} A) : A →+* R
SchemeTheory.commAlgCoefficientMap_eq_algebraMap

The computed coefficient map is precisely the stored native action.

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} [CommRing A]
theorem commAlgCoefficientMap_eq_algebraMap (R : CommAlgCat.{v} A) :
    commAlgCoefficientMap R = algebraMap A R
SchemeTheory.commAlgToAlgCat

The same native object in the category of algebras.

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} [CommRing A]
def commAlgToAlgCat (R : CommAlgCat.{v} A) : AlgCat.{v} A
SchemeTheory.commAlgRingHomToAlgCatHom

Construct the native categorical morphism from the actual ring map and its proved square with the stored coefficient maps.

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} [CommRing A]
def commAlgRingHomToAlgCatHom (R S : CommAlgCat.{v} A) (f : R →+* S)
    (h : f.comp (commAlgCoefficientMap R) = commAlgCoefficientMap S) :
    AlgCat.Hom (commAlgToAlgCat R) (commAlgToAlgCat S)
SchemeTheory.commAlgRingHomToAlgCatHom_toRingHom

The categorical construction retains the given actual RingHom.

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} [CommRing A]
theorem commAlgRingHomToAlgCatHom_toRingHom
    (R S : CommAlgCat.{v} A) (f : R →+* S)
    (h : f.comp (commAlgCoefficientMap R) = commAlgCoefficientMap S) :
    (commAlgRingHomToAlgCatHom R S f h).hom.toRingHom = f