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Mathlib.Topology.Category.TopCat.Limits.Basic

The category of topological spaces has all limits and colimits #

Further, these limits and colimits are preserved by the forgetful functor --- that is, the underlying types are just the limits in the category of types.

A choice of limit cone for a functor F : J ⥤ TopCat. Generally you should just use limit.cone F, unless you need the actual definition (which is in terms of Types.limitCone).

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The chosen cone TopCat.limitCone F for a functor F : J ⥤ TopCat is a limit cone. Generally you should just use limit.isLimit F, unless you need the actual definition (which is in terms of Types.limitConeIsLimit).

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Given a functor F : J ⥤ TopCat and a cone c : Cone (F ⋙ forget) of the underlying functor to types, this is the type c.pt with the infimum of the induced topologies by the maps c.π.app j.

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Given a functor F : J ⥤ TopCat and a cone c : Cone (F ⋙ forget) of the underlying functor to types, this is a cone for F whose point is c.pt with the infimum of the induced topologies by the maps c.π.app j.

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Given a functor F : J ⥤ TopCat and a cone c : Cone (F ⋙ forget) of the underlying functor to types, the limit of F is c.pt equipped with the infimum of the induced topologies by the maps c.π.app j.

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Given a functor F : J ⥤ TopCat and a cocone c : Cocone (F ⋙ forget) of the underlying cocone of types, this is the type c.pt with the supremum of the topologies that are coinduced by the maps c.ι.app j.

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Given a functor F : J ⥤ TopCat and a cocone c : Cocone (F ⋙ forget) of the underlying cocone of types, this is a cocone for F whose point is c.pt with the supremum of the coinduced topologies by the maps c.ι.app j.

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Given a functor F : J ⥤ TopCat and a cocone c : Cocone (F ⋙ forget) of the underlying cocone of types, the colimit of F is c.pt equipped with the supremum of the coinduced topologies by the maps c.ι.app j.

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@[deprecated TopCat.coconeOfCoconeForget (since := "2024-12-31")]

Alias of TopCat.coconeOfCoconeForget.


Given a functor F : J ⥤ TopCat and a cocone c : Cocone (F ⋙ forget) of the underlying cocone of types, this is a cocone for F whose point is c.pt with the supremum of the coinduced topologies by the maps c.ι.app j.

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@[deprecated TopCat.isColimitCoconeOfForget (since := "2024-12-31")]

Alias of TopCat.isColimitCoconeOfForget.


Given a functor F : J ⥤ TopCat and a cocone c : Cocone (F ⋙ forget) of the underlying cocone of types, the colimit of F is c.pt equipped with the supremum of the coinduced topologies by the maps c.ι.app j.

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