Theorems · Definition · category theory
CategoryTheory.Functor.sections
{J : Type u} →
[inst : CategoryTheory.Category.{v, u} J] → (F : CategoryTheory.Functor J (Type w)) → Set ((j : J) → F.obj j)The sections of a functor F : J ⥤ Type are
the choices of a point u j : F.obj j for each j,
such that F.map f (u j) = u j' for every morphism f : j ⟶ j'.
We later use these to define limits in Type and in many concrete categories.
- Defined in
- Mathlib.CategoryTheory.Types.Basic
- Cited by
- 140 results in Mathlib
- Foundations
- Depth 13 from the axioms, rests on 78 definitions · uses propext, Quot.sound
- Assumes
- CategoryTheory.Category
Around this declaration
Dashed lines are statement dependencies; solid lines are citations in proofs.
Cites9
Mathlib declarations this one mentions in its statement or cites explicitly in its proof. Plumbing is filtered out.
- DFunLike.coeproof · cited by 62,936
- Setstatement · cited by 53,352
- CategoryTheory.Categorystatement and proof · cited by 32,673
- Quiver.Homproof · cited by 32,603
- CategoryTheory.Functor.objstatement and proof · cited by 19,642
- CategoryTheory.Functorstatement and proof · cited by 16,252
- CategoryTheory.Functor.mapproof · cited by 8,698
- Set.ofPredproof · cited by 6,101
- CategoryTheory.ConcreteCategory.homproof · cited by 4,022
Cited by267
Results whose statement or proof uses this declaration.
- CategoryTheory.PreGaloisCategory.AutGaloisproof · cited by 12
- SheafOfModules.Presentation.relationsstatement · cited by 10
- CategoryTheory.Functor.sectionsFunctorproof · cited by 8
- CategoryTheory.Limits.Types.sectionOfConestatement · cited by 8
- PresheafOfModules.sectionsproof · cited by 7
- CategoryTheory.Functor.WellOrderInductionData.liftstatement · cited by 7
- Finset.all_card_le_biUnion_card_iff_exists_injectiveproof · cited by 6
- CategoryTheory.Limits.Types.Small.limitConestatement and proof · cited by 6
- AlgebraicGeometry.Scheme.coprodPresheafObjIsostatement · cited by 5
- CategoryTheory.Functor.sectionsEquivHomstatement and proof · cited by 5
- CategoryTheory.Limits.Types.coneOfSectionstatement and proof · cited by 5
- CategoryTheory.Limits.Types.isLimitEquivSectionsstatement and proof · cited by 5
Showing the 200 most cited of 267.