Re: Idempotence and "Replication Insensitivity" are equivalent ?

From: Chris Smith <>
Date: Thu, 21 Sep 2006 01:43:01 -0600
Message-ID: <>

Marshall <> 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
Received on Thu Sep 21 2006 - 09:43:01 CEST

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