W3C home > Mailing lists > Public > www-rdf-logic@w3.org > November 2000

Re: Logic and Using The Semantic Web Toolbox

From: Seth Russell <seth@robustai.net>
Date: Wed, 29 Nov 2000 09:20:47 -0800
Message-ID: <3A253AEE.A97C92D@robustai.net>
To: "Sean B. Palmer" <sean@mysterylights.com>
CC: www-rdf-logic@w3.org, timbl@w3.org
"Sean B. Palmer" wrote:

> How do we get processors to recognize methods like "invertProgram"? Is there
> some way of getting from:-
> [A, isLeftOf, B] to [B, isRightOf, A]

Of course "the schema" needs to know:

[isLeftOf, invert(s), isRightOf]
[isRightOf, invert(s), isLeftOf]

> Or in other words, what is the RDF Schema way of saying [You, do!, invert]
> so that when we invent this property, it automatically finds the reverse of
> all of our triples?

Well "do!" is probably not something that can be defined in RDF Schema.  I did
it by writing a threaded code interperter that crawled on the "schema
statements" themselves.  Here I use the term "schema statements" quite loosely
to mean anything that we hang off of the property resources.  I, however, would
not put those in a separate document as is the popular practice today,  rather I
would include them seamlessly in the same model.

> This is really great, because although:-
>      <not>[A, isLeftOf, B]</not> != [B, is RightOf, A]
> You could say:-
>      if <not>[A, isLeftOf, B]</not> != [B, is RightOf, A]
>      then [A, isLeftOf, B] = [B, is RightOf, A]
>      and also [<not>A</not>, <not>isLeftOf</not>, <not>B</not>] = [B, is
> RightOf, A]!
> Which is exactly what I was looking for, and because the assertions are the
> same that implies that there must *be* a way of implying "not" by simply
> using rdfs...am I right?

I don't know, but I'll take your word for it,  I got a stack overflow when i
tried to read it into my old wOmaN2000 computer.

Seth Russell
Received on Wednesday, 29 November 2000 12:18:06 UTC

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