[Haskell-cafe] Categorical description for vector-space instance of AdditiveGroup (Maybe a)

[Jason McCarty]

On Sat, Sep 13, 2014, at 02:12 PM, trevor cook wrote:
> Jason, John,
> 
> Thanks for the in depth descriptions, it was just what I was looking for.

Glad I could help. I should correct a couple things, though. Rather than
wanting (+ Just x) as a morphism, you'd probably want const Nothing,
which is a monoid morphism if Nothing is the unit of the monoid. But
then the argument about equivalence remains the same.

Also, I think Maybe v isn't even what I called a semi-vector space if v
is; 0 *^ Just x should be Nothing, but it's Just zeroV instead.

I have some more thoughts about this when I get a chance.

-- 
Jason McCarty <jmccarty at sent.com>