Re: Multisets and 3VL
From: David Fetter <david_at_fetter.org>
Date: Tue, 17 Jan 2006 18:37:35 -0600
Message-ID: <XMOdnbt9oZpSEFDenZ2dnUVZ_sWdnZ2d_at_speakeasy.net>
>
> See:
>
> Query Languages for Bags (1993) Leonid Libkin, Limsoon Wong
>
> Multi-sets and multi-relations in Z with an application to a
> bill-of-materials system (1990)
>
> That does not make any obvious sense. What "sharper limits" do you
> have in mind ?
Date: Tue, 17 Jan 2006 18:37:35 -0600
Message-ID: <XMOdnbt9oZpSEFDenZ2dnUVZ_sWdnZ2d_at_speakeasy.net>
vc <boston103_at_hotmail.com> wrote:
>
> David Fetter wrote:
>> Folks, >> >> I've read Date, Darwen and Pascal's ideas on how their relational >> model is based on set theory (I assume they mean ZFC, but it's >> probably not important) and two-valued logic, and they've done a >> thorough job of writing this down. >> >> Has anybody done similar work starting from multiset theory and >> three-valued logic?
>
> See:
>
> Query Languages for Bags (1993) Leonid Libkin, Limsoon Wong
>
> Multi-sets and multi-relations in Z with an application to a
> bill-of-materials system (1990)
Thanks :)
> [...]
>> neutral geometry has sharper limits on what it can prove than >> Euclidean geometry does.
>
> That does not make any obvious sense. What "sharper limits" do you
> have in mind ?
Well, at this stage, it's just fuzzy intuition, but if I had to assign a reason, it would be that I've noticed that when you "know extra stuff" about a problem domain, for example, that every multiset has multiplicity one, or that truth values will only be in {T,F}, you can then use that knowlege to get to places you couldn't have gotten to if you hadn't have it.
Cheers,
David.
-- David Fetter david_at_fetter.org http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Yesterday, upon the stair, I saw a man who wasn't there. He wasn't there again today. I think he's with the NSA.Received on Wed Jan 18 2006 - 01:37:35 CET