[Haskell-cafe] Clarification on proof section of HS: The Craft of FP

[Benjamin Franksen]

On Wednesday 04 May 2005 01:32, Ben Rudiak-Gould wrote:
> This doesn't work in Haskell because Haskell types aren't constructed in
> this way. It's harder to prove properties of types in Haskell (and fewer
> properties actually hold).

Could you explain why this is so? Or rather, what the appropriate technique is 
in Haskell? I assume it has to do with laziness but I have no idea how it 
enters the picture.

Ben