Subject: Re: set.lisp redefines POWERSET / {} for sets
From: Martin RUBEY
Date: Wed, 5 Mar 2003 16:59:45 +0100 (CET)
>
> (c) the nset package that Stavros and I wrote last fall. This code isn't
> in the Maxima CVS; you may
> download nset-1.0.tar.gz from http://www.unk.edu/acad/math/people/willisb/
> Compared to my
> older set package, nset is much better designed, more efficient, better
> tested, and better documented.
> Unlike the other two set packages, nset doesn't redefine powerset.
I agree. However, see my previous post regarding powerset. I think its
stupid to have ten versions of powerset lying around... I'm sure that this
will become more and more important.
BTW, I would encourage you to allow
{a,b,c}
as input for sets. It is much nicer and a lot clearer to type
hypergraph({a,b,c},{[{a,b},2],[{a,c}]});
than
hypergraph(set(a,b,c),set([set(a,b),2],[set(a,c)]));
and I cannot think of any other usage for { and }! (these are symbols
really widely adopted by mathematicians. *Sometimes* they are used to get
Stirling numbers, but this is the same with binomial coefficients!)
from Stavros:
> I did not use def-operator or $matchfix because they define syntax both
> for input and for output, and Barton and I did not want to preempt
> braces just for sets.
Martin
(PLEASE, PLEASE, PLEASE)