Hello, On 10/17/07, Lennart Augustsson <[EMAIL PROTECTED]> wrote: > Check Wikipedia. Peirce law, law of excluded middle, double negation, ... > they are all equivalent and it can be instructive to see how one can derive > one from the other.
Apparently these axioms are not all equivalent (I was quite surprised to learn that :-). Here is some interesting---but perhaps a bit advanced for a tutorial on CH---reading which studies the relation between classical logic and computation: http://coq.inria.fr/~herbelin/publis/icalp-AriHer03-minimal-classical.ps.gz -- Iavor _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe