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Re: LANG, SEM: Re: more on a same-syntax extension from RDF(S) to OWL

From: Jim Hendler <hendler@cs.umd.edu>
Date: Tue, 5 Mar 2002 20:59:21 -0500
Message-Id: <p0510140cb8ab27200f65@[10.0.1.4]>
To: "Jonathan Borden" <jonathan@openhealth.org>, "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <jos.deroo.jd@belgium.agfa.com>, <www-webont-wg@w3.org>
Jonathan-
  You're new to the group, so you may have missed the part in the 
charter that makes it clear that expressing rules pre se is out of 
scope.  Logical entailment stated explicitely would therefore be out 
of scope (i.e. language features where an ontology would somehow add 
entailment rules).  Those rules that are implicit in the 
interpretation of the language (i.e. those that are in the semantic 
of the language) are in scope.
  Note "IF, THEN" perilously close to out of scope.  "OR" within 
scope, "FORALL,=>" right out of there.
  -JH
p.s. If we do legitimize N3 in some way, it would not include the 
rule parts as part of our chartered work, so we could handle parens, 
and brackets and the like, but not the log:implies, etc.




At 12:55 PM -0500 3/5/02, Jonathan Borden wrote:
>Jeremy Carroll wrote:
>
>
>>  > > One of the major benefitts of N3 over
>>  > > RDF (including N-Triples) is the simple ability to write down a set of
>>  > > statements _without asserting them_.
>>
>>
>>  What are the use cases for this ability?
>
>Basically anywhere you see (in N3) { ... } a context is defined in which the
>contents are not necessarily asserted.
>
>Perhaps the simplest use of this is an IF THEN statement or an OR statement
>
>IF {sky color blue} THEN {trees color green}
>
>OR { [sky color blue] [sky color grey] [trees color green] [trees color
>brown] }
>
>or
>
>FORALL ?x such that [?x color blue] => [mary likes ?x]
>
>A simple way to write down a simple formula is the use case.
>
>>
>>  What I have seen so far is the desire to state logical entailments.
>>
>>  This is quite addressable outside RDF rather than inside the graph.
>>  The N3 version could be modelled in RDF as a load of triples, with N3
>>  contexts roughly corresponding to bags of reified triples in RDF.
>
>Yuck!
>
>A simple syntactic device for making a simple IF THEN statement seems like a
>useful thing.
>
>Jonathan


-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
AV Williams Building, Univ of Maryland		  College Park, MD 20742
http://www.cs.umd.edu/users/hendler
Received on Tuesday, 5 March 2002 21:03:25 GMT

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