> 
> > Look at mathematics: equality is polymorphic. Addition is just overloaded.

Sorry, but I cannot resist adding my two cents :)

It depends in what formalism you are doing mathematics in. In set
theory, equality is monomorphic, since all objects live in the same
universe.

Addition is overloaded indeed.


Cheers,

Benjamin


> 
> But as you know (and as I wrote in my previous messages), the
> polymorphic equality in Caml is not at all the "equality in
> mathematics" for many (or most?) datatypes.
>