[Haskell-cafe] ANN: The Typeclassopedia, and request for feedback

[Wolfgang Jeltsch]

Am Dienstag, 17. Februar 2009 00:32 schrieb George Pollard:
> On Mon, 2009-02-16 at 15:30 +0100, Fraser Wilson wrote:
> > Super!  Also, best definition of bottom I've yet seen -- "ignoring _|
> > _, which is a party pooper".  Like good code, it's short, to the
> > point, and obviously correct.
>
> This brings up something I've thought about: On page 8,  it is said that
> Pointed doesn't need to be checked because the theorem comes for free,
> but the free theorems paper was based upon total functions only; does
> having _|_ affect the free theorem for Pointed?

This was my question to Janis Voigtländer after his HaL 3 talk. He said that 
the free theorem stuff also holds in the presence of _|_, it’s just a bit 
more complicated to prove it. At least, this is how I understood it. :-) 

Best wishes,
Wolfgang