The category of R-algebras has all limits #
Further, these limits are preserved by the forgetful functor --- that is, the underlying types are just the limits in the category of types.
instance
AlgebraCat.semiringObj
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
(j : J)
:
Semiring ((F.comp (CategoryTheory.forget (AlgebraCat R))).obj j)
Equations
- AlgebraCat.semiringObj F j = inferInstanceAs (Semiring ↑(F.obj j))
instance
AlgebraCat.algebraObj
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
(j : J)
:
Algebra R ((F.comp (CategoryTheory.forget (AlgebraCat R))).obj j)
Equations
- AlgebraCat.algebraObj F j = inferInstanceAs (Algebra R ↑(F.obj j))
def
AlgebraCat.sectionsSubalgebra
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
:
Subalgebra R ((j : J) → ↑(F.obj j))
The flat sections of a functor into AlgebraCat R
form a submodule of all sections.
Equations
- One or more equations did not get rendered due to their size.
Instances For
instance
AlgebraCat.instRingElemForallObjCompForgetSections
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
:
Ring ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections
instance
AlgebraCat.instAlgebraElemForallObjCompForgetSections
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
:
Algebra R ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections
instance
AlgebraCat.instSmallSubtypeForallCarrierObjMemSubalgebraSectionsSubalgebra
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
[Small.{w, max v w} ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections]
:
Equations
- ⋯ = ⋯
instance
AlgebraCat.limitSemiring
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
[Small.{w, max v w} ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections]
:
Ring (CategoryTheory.Limits.Types.Small.limitCone (F.comp (CategoryTheory.forget (AlgebraCat R)))).pt
instance
AlgebraCat.limitAlgebra
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
[Small.{w, max v w} ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections]
:
Algebra R (CategoryTheory.Limits.Types.Small.limitCone (F.comp (CategoryTheory.forget (AlgebraCat R)))).pt
Equations
def
AlgebraCat.limitπAlgHom
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
[Small.{w, max v w} ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections]
(j : J)
:
(CategoryTheory.Limits.Types.Small.limitCone (F.comp (CategoryTheory.forget (AlgebraCat R)))).pt →ₐ[R] (F.comp (CategoryTheory.forget (AlgebraCat R))).obj j
limit.π (F ⋙ forget (AlgebraCat R)) j
as a AlgHom
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
def
AlgebraCat.HasLimits.limitCone
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
[Small.{w, max v w} ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections]
:
Construction of a limit cone in AlgebraCat R
.
(Internal use only; use the limits API.)
Equations
- One or more equations did not get rendered due to their size.
Instances For
def
AlgebraCat.HasLimits.limitConeIsLimit
{R : Type u}
[CommRing R]
{J : Type v}
[CategoryTheory.Category.{t, v} J]
(F : CategoryTheory.Functor J (AlgebraCat R))
[Small.{w, max v w} ↑(F.comp (CategoryTheory.forget (AlgebraCat R))).sections]
:
Witness that the limit cone in AlgebraCat R
is a limit cone.
(Internal use only; use the limits API.)
Equations
- One or more equations did not get rendered due to their size.
Instances For
The category of R-algebras has all limits.
Equations
- ⋯ = ⋯
Equations
- AlgebraCat.forget₂RingPreservesLimits = AlgebraCat.forget₂RingPreservesLimitsOfSize
The forgetful functor from R-algebras to R-modules preserves all limits.
Equations
- One or more equations did not get rendered due to their size.
Equations
- AlgebraCat.forget₂ModulePreservesLimits = AlgebraCat.forget₂ModulePreservesLimitsOfSize
The forgetful functor from R-algebras to types preserves all limits.
Equations
- One or more equations did not get rendered due to their size.
Equations
- AlgebraCat.forgetPreservesLimits = AlgebraCat.forgetPreservesLimitsOfSize