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DerivedAlgGeo.CategoryTheory.Triangulated.FourierMukai.DualCotwistKernel

Kernel realizations of left-adjunction dual cotwists #

Let Φ_Q ⊣ Φ_P, where Φ_P : X ⥤ Y is a Fourier--Mukai transform and Φ_Q : Y ⥤ X is its supplied kernel-presented left adjoint. The adjunction counit is

Φ_P ⋙ Φ_Q ⟶ id_X.

Its cone is conventionally the dual cotwist of the original functor Φ_P. This file supplies the semantic left-adjunction API while reusing CounitKernelData and CounitKernelConeData with the correspondences swapped through LeftAdjointKernelData.toRightAdjointKernelData.

Thus an ordinary kernel arrow conv P Q ⟶ O_Δ, together with its exact transform equation, has a noncanonically selected enhanced representative and cone. Exact kernel evaluation produces the source-natural, pointwise distinguished family

Φ_P ⋙ Φ_Q ⟶ id_X ⟶ dualCotwist ⟶ (Φ_P ⋙ Φ_Q)⟦1⟧.

No new adjunction, cone, normalization, or rotation is constructed here. The dual cotwist remains choice-dependent; it is not asserted exact, invertible, canonical, or spherical.

@[reducible, inline]
abbrev CategoryTheory.Triangulated.FourierMukai.DualCotwistKernelData {X : Type uX} {Y : Type uY} {W₁ : Type u₁} {W₂ : Type u₂} {W : Type uW} [Category.{vX, uX} X] [Category.{vY, uY} Y] [Category.{v₁, u₁} W₁] [Category.{v₂, u₂} W₂] [Category.{vW, uW} W] (C : Correspondence X Y W₁) (C' : Correspondence Y X W₂) (E : Correspondence X X W) (P : W₁) (L : LeftAdjointKernelData C C' P) (D : ConvolutionData C C' E) (U : UnitKernelData E) :
Type vW

An ordinary kernel arrow realizing the counit of a kernel-presented left adjunction, named as the dual-cotwist input for the original functor.

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    @[reducible, inline]
    abbrev CategoryTheory.Triangulated.FourierMukai.DualCotwistKernelConeData {X : Type uX} {Y : Type uY} {W₁ : Type u₁} {W₂ : Type u₂} {W : Type uW} [Category.{vX, uX} X] [Category.{vY, uY} Y] [Category.{v₁, u₁} W₁] [Category.{v₂, u₂} W₂] [Category.{vW, uW} W] (C : Correspondence X Y W₁) (C' : Correspondence Y X W₂) (E : Correspondence X X W) (e : Enhancement W) (P : W₁) (L : LeftAdjointKernelData C C' P) (D : ConvolutionData C C' E) (U : UnitKernelData E) :
    Type (max uE vE)

    An enhanced representative and chosen cone for a left-adjunction counit kernel arrow, named as the dual-cotwist input for the original functor.

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      The specialized transform equation for the left-adjunction counit.

      noncomputable def CategoryTheory.Triangulated.FourierMukai.DualCotwistKernelData.ofFull {X : Type uX} {Y : Type uY} {W₁ : Type u₁} {W₂ : Type u₂} {W : Type uW} [Category.{vX, uX} X] [Category.{vY, uY} Y] [Category.{v₁, u₁} W₁] [Category.{v₂, u₂} W₂] [Category.{vW, uW} W] {C : Correspondence X Y W₁} {C' : Correspondence Y X W₂} {E : Correspondence X X W} {P : W₁} {L : LeftAdjointKernelData C C' P} {D : ConvolutionData C C' E} {U : UnitKernelData E} [E.kernelTransform.Full] :
      DualCotwistKernelData C C' E P L D U

      Fullness of the kernel transform is sufficient to realize the left-adjunction counit by an ordinary kernel morphism.

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        noncomputable def CategoryTheory.Triangulated.FourierMukai.DualCotwistKernelData.toConeData {X : Type uX} {Y : Type uY} {W₁ : Type u₁} {W₂ : Type u₂} {W : Type uW} [Category.{vX, uX} X] [Category.{vY, uY} Y] [Category.{v₁, u₁} W₁] [Category.{v₂, u₂} W₂] [Category.{vW, uW} W] {C : Correspondence X Y W₁} {C' : Correspondence Y X W₂} {E : Correspondence X X W} {P : W₁} {L : LeftAdjointKernelData C C' P} {D : ConvolutionData C C' E} {U : UnitKernelData E} (S : DualCotwistKernelData C C' E P L D U) (e : Enhancement W) :
        DualCotwistKernelConeData C C' E e P L D U

        Choose a closed representative and dg cone for the dual-cotwist counit kernel arrow. Both choices are noncanonical.

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          @[reducible, inline]
          abbrev CategoryTheory.Triangulated.FourierMukai.DualCotwistKernelConeData.dualCotwistKernel {X : Type uX} {Y : Type uY} {W₁ : Type u₁} {W₂ : Type u₂} {W : Type uW} [Category.{vX, uX} X] [Category.{vY, uY} Y] [Category.{v₁, u₁} W₁] [Category.{v₂, u₂} W₂] [Category.{vW, uW} W] {C : Correspondence X Y W₁} {C' : Correspondence Y X W₂} {E : Correspondence X X W} {e : Enhancement W} {P : W₁} {L : LeftAdjointKernelData C C' P} {D : ConvolutionData C C' E} {U : UnitKernelData E} (S : DualCotwistKernelConeData C C' E e P L D U) :
          W

          The selected enhanced counit cone read as an ordinary kernel.

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            @[reducible, inline]
            abbrev CategoryTheory.Triangulated.FourierMukai.DualCotwistKernelConeData.dualCotwist {X : Type uX} {Y : Type uY} {W₁ : Type u₁} {W₂ : Type u₂} {W : Type uW} [Category.{vX, uX} X] [Category.{vY, uY} Y] [Category.{v₁, u₁} W₁] [Category.{v₂, u₂} W₂] [Category.{vW, uW} W] {C : Correspondence X Y W₁} {C' : Correspondence Y X W₂} {E : Correspondence X X W} {e : Enhancement W} {P : W₁} {L : LeftAdjointKernelData C C' P} {D : ConvolutionData C C' E} {U : UnitKernelData E} (S : DualCotwistKernelConeData C C' E e P L D U) :

            The transform of the selected cone kernel: the choice-dependent ordinary dual cotwist.

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              The named dual-cotwist kernel presents the dual cotwist definitionally.

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                The dual cotwist is a kernel functor for the endocorrespondence on X. This does not assert exactness or invertibility.

                The transported second map from the identity to the dual cotwist.

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                  The transported connecting map from the dual cotwist to the shifted left-adjoint composite.

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                    The source-natural dual-cotwist triangle for the original functor Φ_P : X ⥤ Y.

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                      At the natural-transformation level, the first map is strictly the left-adjunction counit.