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RE: Reification quoting in RDF/N3 was: A note comparing Conceptua l Graphs and RDF/Semantic Web

From: Bill dehOra <BdehOra@interx.com>
Date: Fri, 19 Jan 2001 09:45:47 -0000
Message-ID: <23CF4BF2C499D411907E00508BDC95E131F884@ntmews_01.interx.com>
To: "'Sean B. Palmer'" <sean@mysterylights.com>, Bill dehOra <BdehOra@interx.com>, "'Dan Brickley'" <danbri@w3.org>, "McBride, Brian" <bwm@hplb.hpl.hp.com>
Cc: Tim Berners-Lee <timbl@w3.org>, www-rdf-logic@w3.org

:> Suppose we wanted to do this for real. 'Fred' is not a URI.
:
:*sigh* This is the age-old problem where we want to make 
:assertions abotut
:things that don't have URIs in RDF. My take on this is that you simply
:*give* them a URI:-
:
:@prefix : <#>
::bill :loves :jane
:
:Now you don't need to explicitly have a URI "<#bill>" for 
:<#bill> to exist:
:you just talk about it, and call it a person as best you can:-

One cautious, baseline way of thinking about string literals, is that for
machine purposes they are non-unique and have no semantics.

At some point we have to jump from machine meaningless to machine
meaningful. If this is the case, then what does making resources out of
literals give us?  There is at least one sensible answer: allow them to
become the subject of statements, since, what we really want to do with a
string literal is predicate it as soon as possible. Naturally we want to do
this in an automated way. I emphasise machinery here, since it is an easy
trap to read semantics into things which aren't there for the purposes of
computation. Human readable formats like XML do have a downside. In this
case it's largely irrelevant that they look like names to us.
  
Now one way I can see of lifting a literal into a name is having some
semantics around the predicate "loves". So a machine processing this:

	bill :loves :jane

can infer a hypothesis that the subject and object of this statement are
proper names/nouns. That's a narrow range for "loves" though. Consider, the
statement (which is more likely to be true in any case):

	bill :loves :scotch

So given that predicates such as loves will impose ambiguity, we'll need
software that can generate an inference to the best possible hypothesis of
the subject and object of any statement that in turn has the predicate loves
(where ambuigity really means more than one hypothesis can fit the data). In
essence, when I need to deal with string literals in RDF, I want my machine
to put on its natural language processing/tagging hat. And hope it has a
good abductive inferencing engine :) I also note that conceptual graphs is a
particulary useful technology for this sort of problem.


:Do not start writing things about string literals,
:because it doesn't mean anything: write about URIs, please :-)

Well we have to articulate something about them, they're a normative aspect
of the M&S after all. 


-Bill

----
Bill de hÓra  :  InterX  :  bdehora@interx.com
Received on Friday, 19 January 2001 04:47:34 GMT

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