Discrete PUnit
has limits and colimits #
Mostly for the sake of constructing trivial examples, we show all (co)cones into Discrete PUnit
are (co)limit (co)cones. We also show that such (co)cones exist, and that Discrete PUnit
has all
(co)limits.
def
CategoryTheory.Limits.punitCone
{J : Type v}
[CategoryTheory.Category.{v', v} J]
{F : CategoryTheory.Functor J (CategoryTheory.Discrete PUnit.{u_1 + 1} )}
:
A trivial cone for a functor into PUnit
. punitConeIsLimit
shows it is a limit.
Equations
- CategoryTheory.Limits.punitCone = { pt := { as := PUnit.unit }, π := (((CategoryTheory.Functor.const J).obj { as := PUnit.unit }).punitExt F).hom }
Instances For
def
CategoryTheory.Limits.punitCocone
{J : Type v}
[CategoryTheory.Category.{v', v} J]
{F : CategoryTheory.Functor J (CategoryTheory.Discrete PUnit.{u_1 + 1} )}
:
A trivial cocone for a functor into PUnit
. punitCoconeIsLimit
shows it is a colimit.
Equations
- CategoryTheory.Limits.punitCocone = { pt := { as := PUnit.unit }, ι := (F.punitExt ((CategoryTheory.Functor.const J).obj { as := PUnit.unit })).hom }
Instances For
def
CategoryTheory.Limits.punitConeIsLimit
{J : Type v}
[CategoryTheory.Category.{v', v} J]
{F : CategoryTheory.Functor J (CategoryTheory.Discrete PUnit.{u_1 + 1} )}
{c : CategoryTheory.Limits.Cone F}
:
Any cone over a functor into PUnit
is a limit cone.
Equations
- CategoryTheory.Limits.punitConeIsLimit = { lift := fun (s : CategoryTheory.Limits.Cone F) => CategoryTheory.eqToHom ⋯, fac := ⋯, uniq := ⋯ }
Instances For
def
CategoryTheory.Limits.punitCoconeIsColimit
{J : Type v}
[CategoryTheory.Category.{v', v} J]
{F : CategoryTheory.Functor J (CategoryTheory.Discrete PUnit.{u_1 + 1} )}
{c : CategoryTheory.Limits.Cocone F}
:
Any cocone over a functor into PUnit
is a colimit cocone.
Equations
- CategoryTheory.Limits.punitCoconeIsColimit = { desc := fun (s : CategoryTheory.Limits.Cocone F) => CategoryTheory.eqToHom ⋯, fac := ⋯, uniq := ⋯ }