On the hskell list, spj wrote > I forget whether I've aired this on the list, but I'm seriously > thinking = that we should change 'forall' to 'exists' in existential > data constructors Thanks! It made me wonder what colour the sky is on planet Haskell. >From a Curry-Howard point of view, (I think) the quantifiers are currently the wrong way round. It is actually painful! Peter Hancock