Portability | GADTs, TFs, MPTCs |
---|---|
Stability | provisional |
Maintainer | Edward Kmett <ekmett@gmail.com> |
Safe Haskell | Trustworthy |
Yoneda Reduction of presheafs
- data Yoneda f a where
- liftYoneda :: f a -> Yoneda f a
- lowerYoneda :: Contravariant f => Yoneda f a -> f a
Documentation
A Contravariant
functor (aka presheaf) suitable for Yoneda reduction.
Contravariant (Yoneda f) | |
Valued f => Valued (Yoneda f) | |
Coindexed f => Coindexed (Yoneda f) | |
Representable f => Representable (Yoneda f) | |
Adjunction f g => Adjunction (Yoneda f) (Yoneda g) |
liftYoneda :: f a -> Yoneda f aSource
Yoneda expansion of a presheaf
liftYoneda
.lowerYoneda
≡id
lowerYoneda
.liftYoneda
≡id
lowerYoneda :: Contravariant f => Yoneda f a -> f aSource
Yoneda reduction on a presheaf