mathlib3 documentation

category_theory.monad.products

Algebras for the coproduct monad #

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The functor Y ↦ X ⨿ Y forms a monad, whose category of monads is equivalent to the under category of X. Similarly, Y ↦ X ⨯ Y forms a comonad, whose category of comonads is equivalent to the over category of X.

TODO #

Show that over.forget X : over X ⥤ C is a comonadic left adjoint and under.forget : under X ⥤ C is a monadic right adjoint.

The forward direction of the equivalence from coalgebras for the product comonad to the over category.

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The backward direction of the equivalence from coalgebras for the product comonad to the over category.

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The forward direction of the equivalence from algebras for the coproduct monad to the under category.

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The backward direction of the equivalence from algebras for the coproduct monad to the under category.

Equations