Peter Verswyvelen wrote: > Jerzy wrote: >> The relational syntax of Prolog is more "universal" than the functional >> notation, since you have logic variables and logical-non-determinism, and > > Isn't this just because mathematically, a function *is* a relation, but > not vice versa? A relation being just a subset of a Cartesian product of > sets, while a function being a special kind of relation for which each > element in the domain has exactly one image? So relations are inherently > much more universal than functions, but they are not that practical to > work with (for a computer and/or human?).
You can as well regard a relation as a special sort of function, i.e. define relation ~ as a function A x B -> Bool by (a,b) |-> a ~ b. Cheers Ben _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
