Preservations of limits for bifunctors #
Let G : C₁ ⥤ C₂ ⥤ C
a functor. We introduce a class PreservesLimit₂ K₁ K₂ G
that encodes
the hypothesis that the curried functor F : C₁ × C₂ ⥤ C
preserves limits of the diagram
K₁ × K₂ : J₁ × J₂ ⥤ C₁ × C₂
. We give a basic API to extract isomorphisms
$\lim_{(j_1,j_2)} G(K_1(j_1), K_2(j_2)) \simeq G(\lim K_1, \lim K_2)$
out of this typeclass.
Given a bifunctor G : C₁ ⥤ C₂ ⥤ C
, diagrams K₁ : J₁ ⥤ C₁
and K₂ : J₂ ⥤ C₂
, and cocones
over these diagrams, G.mapCocone₂ c₁ c₂
is the cocone over the diagram J₁ × J₂ ⥤ C
obtained
by applying G
to both c₁
and c₂
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Given a bifunctor G : C₁ ⥤ C₂ ⥤ C
, diagrams K₁ : J₁ ⥤ C₁
and K₂ : J₂ ⥤ C₂
, and cones
over these diagrams, G.mapCone₂ c₁ c₂
is the cone over the diagram J₁ × J₂ ⥤ C
obtained
by applying G
to both c₁
and c₂
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
A functor PreservesColimit₂ K₁ K₂
if whenever c₁
is a colimit cocone and c₂
is a colimit
cocone then G.mapCocone₂ c₁ c₂
is a colimit cocone. This can be thought of as the data of an
isomorphism
$\mathrm{colim}_{(j_1,j_2)} G(K_1(j_1),K_2(j_2)) \simeq G(\mathrm{colim} K_1,\mathrm{colim} K_2)$.
Instances
A functor PreservesLimit₂ K₁ K₂
if whenever c₁
is a limit cone and c₂
is a limit
cone then G.mapCone₂ c₁ c₂
is a limit cone. This can be thought of as the data of an
isomorphism $\lim_{(j_1,j_2)} G(K_1(j_1), K_2(j_2)) \simeq G(\lim K_1, \lim K_2)$.
Instances
If PreservesColimit₂ K₁ K₂ G
, obtain that G.mapCocone₂ c₁ c₂
is a colimit cocone
whenever c₁ c₂ are colimit cocones.
Equations
- CategoryTheory.Limits.isColimitOfPreserves₂ G hc₁ hc₂ = ⋯.some
Instances For
If PreservesLimit₂ K₁ K₂ G
, obtain that G.mapCone₂ c₁ c₂
is a limit cone
whenever c₁ c₂ are limit cones.
Equations
- CategoryTheory.Limits.isLimitOfPreserves₂ G hc₁ hc₂ = ⋯.some
Instances For
Given a PreservesColimit₂
instance, extract the isomorphism between
a colimit of uncurry.obj (whiskeringLeft₂ C|>.obj K₁|>.obj K₂|>.obj G)
and
(G.obj c₁).obj c₂
where c₁ (resp. c₂) is a colimit of K₁
(resp K₂
).
Equations
Instances For
Characterize the inverse direction of the isomorphism
PreservesColimit₂.isoObjCoconePointsOfIsColimit
w.r.t the canonical maps to the colimit.
Characterize the forward direction of the isomorphism
PreservesColimit₂.isoObjCoconePointsOfIsColimit
w.r.t the canonical maps to the colimit.
Extract the isomorphism between
colim (uncurry.obj (whiskeringLeft₂ C|>.obj K₁|>.obj K₂|>.obj G))
and
(G.obj (colim K₁)).obj (colim K₂)
from a PreservesColimit₂
instance, provided the relevant
colimits exist.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Characterize the forward direction of the isomorphism
PreservesColimit₂.isoColimitUncurryWhiskeringLeft₂
w.r.t the canonical maps to the colimit.
Characterize the forward direction of the isomorphism
PreservesColimit₂.isoColimitUncurryWhiskeringLeft₂
w.r.t the canonical maps to the colimit.
If a bifunctor preserves separately colimits of K₁
in the first variable and colimits
of K₂
in the second variable, then it preserves colimit of the pair K₁, K₂
.
Given a PreservesLimit₂
instance, extract the isomorphism between
a limit of uncurry.obj (whiskeringLeft₂ C|>.obj K₁|>.obj K₂|>.obj G)
and
(G.obj c₁).obj c₂
where c₁ (resp. c₂) is a limit of K₁
(resp K₂
).
Equations
- CategoryTheory.Limits.PreservesLimit₂.isoObjConePointsOfIsLimit G hc₁ hc₂ hc₃ = (CategoryTheory.Limits.isLimitOfPreserves₂ G hc₁ hc₂).conePointUniqueUpToIso hc₃
Instances For
Characterize the forward direction of the isomorphism
PreservesLimit₂.isoObjConePointsOfIsLimit
w.r.t the canonical maps to the limit.
Characterize the inverse direction of the isomorphism
PreservesLimit₂.isoObjConePointsOfIsLimit
w.r.t the canonical maps to the limit.
Extract the isomorphism between
colim (uncurry.obj (whiskeringLeft₂ C|>.obj K₁|>.obj K₂|>.obj G))
and
(G.obj (colim K₁)).obj (colim K₂)
from a PreservesLimit₂
instance, provided the relevant
limits exist.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Characterize the inverse direction of the isomorphism
PreservesLimit₂.isoLimitUncurryWhiskeringLeft₂
w.r.t the canonical maps to the limit.
Characterize the forward direction of the isomorphism
PreservesLimit₂.isoLimitUncurryWhiskeringLeft₂
w.r.t the canonical maps to the limit.
If a bifunctor preserves separately limits of K₁
in the first variable and limits
of K₂
in the second variable, then it preserves colimit of the pair of cones K₁, K₂
.