Documentation

Mathlib.CategoryTheory.Adjunction.Limits

Adjunctions and limits #

A left adjoint preserves colimits (CategoryTheory.Adjunction.leftAdjointPreservesColimits), and a right adjoint preserves limits (CategoryTheory.Adjunction.rightAdjointPreservesLimits).

Equivalences create and reflect (co)limits. (CategoryTheory.Adjunction.isEquivalenceCreatesLimits, CategoryTheory.Adjunction.isEquivalenceCreatesColimits, CategoryTheory.Adjunction.isEquivalenceReflectsLimits, CategoryTheory.Adjunction.isEquivalenceReflectsColimits,)

In CategoryTheory.Adjunction.coconesIso we show that when F ⊣ G, the functor associating to each Y the cocones over K ⋙ F with cone point Y is naturally isomorphic to the functor associating to each Y the cocones over K with cone point G.obj Y.

The right adjoint of Cocones.functoriality K F : Cocone K ⥤ Cocone (K ⋙ F).

Auxiliary definition for functorialityIsLeftAdjoint.

Equations
  • One or more equations did not get rendered due to their size.
Instances For

    The counit for the adjunction for Cocones.functoriality K F : Cocone K ⥤ Cocone (K ⋙ F).

    Auxiliary definition for functorialityIsLeftAdjoint.

    Equations
    • One or more equations did not get rendered due to their size.
    Instances For

      The functor Cocones.functoriality K F : Cocone K ⥤ Cocone (K ⋙ F) is a left adjoint.

      Equations
      • One or more equations did not get rendered due to their size.
      Instances For

        The left adjoint of Cones.functoriality K G : Cone K ⥤ Cone (K ⋙ G).

        Auxiliary definition for functorialityIsRightAdjoint.

        Equations
        • One or more equations did not get rendered due to their size.
        Instances For

          The unit for the adjunction for Cones.functoriality K G : Cone K ⥤ Cone (K ⋙ G).

          Auxiliary definition for functorialityIsRightAdjoint.

          Equations
          • One or more equations did not get rendered due to their size.
          Instances For

            The functor Cones.functoriality K G : Cone K ⥤ Cone (K ⋙ G) is a right adjoint.

            Equations
            • One or more equations did not get rendered due to their size.
            Instances For

              auxiliary construction for coconesIso

              Equations
              Instances For

                auxiliary construction for coconesIso

                Equations
                Instances For
                  def CategoryTheory.Adjunction.conesIsoComponentHom {C : Type u₁} [CategoryTheory.Category.{v₁, u₁} C] {D : Type u₂} [CategoryTheory.Category.{v₂, u₂} D] {F : CategoryTheory.Functor C D} {G : CategoryTheory.Functor D C} (adj : F G) {J : Type u} [CategoryTheory.Category.{v, u} J] {K : CategoryTheory.Functor J D} (X : Cᵒᵖ) (t : (CategoryTheory.Functor.comp F.op ((CategoryTheory.cones J D).toPrefunctor.obj K)).toPrefunctor.obj X) :
                  ((CategoryTheory.cones J C).toPrefunctor.obj (CategoryTheory.Functor.comp K G)).toPrefunctor.obj X

                  auxiliary construction for conesIso

                  Equations
                  Instances For
                    def CategoryTheory.Adjunction.conesIsoComponentInv {C : Type u₁} [CategoryTheory.Category.{v₁, u₁} C] {D : Type u₂} [CategoryTheory.Category.{v₂, u₂} D] {F : CategoryTheory.Functor C D} {G : CategoryTheory.Functor D C} (adj : F G) {J : Type u} [CategoryTheory.Category.{v, u} J] {K : CategoryTheory.Functor J D} (X : Cᵒᵖ) (t : ((CategoryTheory.cones J C).toPrefunctor.obj (CategoryTheory.Functor.comp K G)).toPrefunctor.obj X) :
                    (CategoryTheory.Functor.comp F.op ((CategoryTheory.cones J D).toPrefunctor.obj K)).toPrefunctor.obj X

                    auxiliary construction for conesIso

                    Equations
                    Instances For

                      When F ⊣ G, the functor associating to each Y the cocones over K ⋙ F with cone point Y is naturally isomorphic to the functor associating to each Y the cocones over K with cone point G.obj Y.

                      Equations
                      • One or more equations did not get rendered due to their size.
                      Instances For

                        When F ⊣ G, the functor associating to each X the cones over K with cone point F.op.obj X is naturally isomorphic to the functor associating to each X the cones over K ⋙ G with cone point X.

                        Equations
                        • One or more equations did not get rendered due to their size.
                        Instances For