Am Samstag, 14. März 2009 23:33 schrieben Sie: > On Fri, 13 Mar 2009, Wolfgang Jeltsch wrote: > > Class instances should satisfy certain laws. (Although these laws are > > often not stated explicitely, they are assumed to hold by users of the > > class and they should hold to make the instance sensible.) In the case of > > Num, I would expect num + negate num to equal num. > > "equal zero" ?
Exactly. Best wishes, Wolfgang _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
