[Haskell-cafe] Wikipedia on first-class object

[Peter Verswyvelen]

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?).

Gee, I should not talk about math here, as you "category theory" guys know a thousand times more math than I do ;-)

Cheers,
Peter