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Re: [Axiom-math] missing exports in Finite DirectProduct and Product
From: |
Martin Rubey |
Subject: |
Re: [Axiom-math] missing exports in Finite DirectProduct and Product |
Date: |
18 Oct 2007 08:39:06 +0200 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 |
"Bill Page" <address@hidden> writes:
> I would be interested in your opinions about this approach to
> providing Cartesian products for the Axiom library.
I think you did something quite interesting. Unfortunately, I'm very busy
right now, but you might be interested in digging up a proposal of mine I made
a year ago or so, concerning StepThrough. It was rejected back then (for good
theoretic reasons), but I still have the feeling that the behaviour I
critisized should be changed. The following also goes into that direction:
> I think it is interesting to see how domains in the category Finite able to
> participate like "sets" in the language. Of course it is also possible to
> represent countably infinite sets in Axiom via the Stream domain. This
> suggests the that the category constructor StepThrough could also usefully be
> provided with an export that expands to such Stream. Perhaps the underlying
> Spad language should support this sort of expansion of Finite and countably
> infinite domains as a standard form of iterator in the [ ... for i in ... ]
> construction?
> Of course Aldor already has implemented some basic abstractions of this kind
> but it is not entirely obvious to me how best to extend Axiom's library and
> still stay within the limitations of the current Spad language.
Really, what is missing are generators. I do not think that adding them to
SPAD in a naive manner would be too difficult, but I never tried.
Many thanks for your effort,
Martin