[Haskell-cafe] Re: Monads that are Comonads and the role of Adjunction

Yitzchak Gale gale at sefer.org
Mon Dec 17 04:34:12 EST 2007

Derek Elkins wrote:
> There is another very closely related adjunction that is less often
> mentioned.
> ((-)->C)^op -| (-)->C
> or
> a -> b -> C ~ b -> a -> C
> This gives rise to the monad,
> M a = (a -> C) -> C
> this is also exactly the comonad it gives rise to (in the op category
> which ends up being the above monad in the "normal" category).

That looks very like the type of mfix. Is this
related to MonadFix?


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