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Re: Logic and Using The Semantic Web Toolbox

From: Seth Russell <seth@robustai.net>
Date: Wed, 29 Nov 2000 12:39:05 -0800
Message-ID: <3A256968.7C24AB80@robustai.net>
To: "Sean B. Palmer" <sean@mysterylights.com>
CC: www-rdf-logic@w3.org, timbl@w3.org
"Sean B. Palmer" wrote:

> Summary of this message: I truly believe that there must be a way of
> schematically asserting a 'not'!

Let me make another take on this.  There probably is not any way to express the
essence of "not" in a purely declarative way.  Were I a professor of logic I
would set out to find that assertion proved in the literature, and failing that
I would attempt to prove it myself.  But we can easily make "not" mean something
in a running system.  For example, let's say that our system believes the purely
declarative representation: [A, not, [s1, isLeftOf, B]].  Now that just sits
there representing our fact exactly and explicitly; but doesn't mean shit.
Until perhaps we write the "schema" for "not" and then instigate a running
process:

The schema:

[not, Boolean, notBoolianProgram]

[Boolean, rdf:type, method]

[notBooleanProgram, rdf_1, firstAction]
[notBooleanProgram, rdf_1, secondAction]
.... for however many actions are necessary

So now I can write the sequence of actions hanging off the notBooleanProgram
such that the running process will take a [False] attitude towards any statement
it encounters or implies that looks like [A, isLeftOf, B].  In other words if
the active process's attention is on [A, isLeftOf, B] the process will ~feel~
false.   I'm being a bit cute here, really all I'm saying is that there will be
a Boolean variable in the process object and the value of that variable will be
"0" when the process's attention pointer is on the proposition above.

Does that make any sense ?

Seth Russell
Received on Wednesday, 29 November 2000 15:36:24 UTC

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