From: Alexis Gallagher
Subject: CL library for point-set theory
Date: 
Message-ID: <dt4g19$9ld$1@news.ox.ac.uk>
Hello,

I was wondering if there's a CL library that supports sets as a data 
structure and operations in elementary topology.

I'd like not only the set as a basic data structure, but higher order 
operations that let me generate powersets, test if a set and a set of 
open sets define a topology, generate the open sets from a topological 
basis set, convert between neighborhood functions and accessibility 
relations, etc..

I know that CL includes the functions union, intersection, and subset. 
Using these I defined an equality relation for sets on proper lists. 
 From there I've stated to build up some of the functions I needed 
(powerset, cartesian product, etc..).

But as I keep working, I suspect just using proper lists for sets is 
quite inadequate, as I am starting to run into subtleties involving sets 
defined as ordered pairs, sets of sets, correct handling of the empty 
set, etc.. I'm not sure if I should define a set class using CLOS, or 
what, since I'm quite new to common lisp (longtime lurker, first time 
poster here). So I'm also wondering if someone else has already done 
this properly, or at least defined a set data structure I can build off.

I checked the cl-directory, google, and the other usual suspects, and 
didn't find anything besides a scheme library called "galore", which I 
suppose I could port parts of.

Thanks,
alexis
From: Nicolas Neuss
Subject: Re: CL library for point-set theory
Date: 
Message-ID: <87accpmw51.fsf@ortler.iwr.uni-heidelberg.de>
Alexis Gallagher <······@alexisgallagher.com> writes:

> Hello,
>
> I was wondering if there's a CL library that supports sets as a data
> structure and operations in elementary topology.

Maybe those links are interesting for you:

http://www-fourier.ujf-grenoble.fr/~sergerar/Kenzo/
http://www.cs.cornell.edu/Info/Projects/SimLab/

Yours, Nicolas.
From: Timofei Shatrov
Subject: Re: CL library for point-set theory
Date: 
Message-ID: <43f81f95.3460095@news.readfreenews.net>
On Fri, 17 Feb 2006 23:57:14 +0100, Nicolas Neuss
<··················@iwr.uni-heidelberg.de> tried to confuse everyone
with this message:

>Alexis Gallagher <······@alexisgallagher.com> writes:
>
>> Hello,
>>
>> I was wondering if there's a CL library that supports sets as a data
>> structure and operations in elementary topology.
>
>Maybe those links are interesting for you:
>
>http://www-fourier.ujf-grenoble.fr/~sergerar/Kenzo/

Wow, this program is amazing. Sadly it is unaware of such concepts as
packages and ASDF, and the fact that it's working on CLISP (you have to
change +compiled-extension+ constant). Too bad I'm not a topologist so I
can't get the most out of this program - homologies are one thing I
never understood.

-- 
|WAR HAS NEVER SOLVED ANYTHING|,----- Timofei Shatrov aka Grue---------.
|(except for ending slavery,  ||mail: grue at mail.ru ================ |
|   fascism and communism)    ||============= http://grue3.tripod.com  |
|...and Saddam's dictatorship |`----------------------------------[4*72]
comp.lang.lisp / 2006 / feb