Re: Idempotence and "Replication Insensitivity" are equivalent ?

Marshall <marshall.spight_at_gmail.com> wrote:
> Well, earlier I said that either f must be associative and commutative,
> or else the fold has to be over an ordered collection. Does that
> suffice?

It's not true. There exist perfectly well-defined folds over functions that are not associative and commutative. They all start from a value other than the identity of f, but they do exist.

Or did you mean that you just want to define them out of consideration. I suppose no one could say you were wrong, but then COUNT would become impossible to define under such a system.

-- 
Chris Smith