On Sun, Jul 6, 2014 at 12:27 AM, Brent Yorgey <byorgey@seas.upenn.edu> wrote:
On Sat, Jul 05, 2014 at 02:51:07AM -0300, Dimitri DeFigueiredo wrote:
>
> However, I don't think there is any way this mapping of types cannot
> be injective in Haskell. It seems that a type constructor, when
> called with two distinct type will always yield another two
> *distinct* types. (E.g. Int and Double yield Maybe Int and Maybe
> Double) So, it seems that Functors in Haskell are actually more
> restrictive than functors can be in general. Is this observation
> correct or did I misunderstand something?

Yes, that's correct.

Why is that correct? How would you show that?

-- Kim-Ee