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Re: [OWL compatibility] #, ## in OWL compatibility

From: Chris Welty <cawelty@gmail.com>
Date: Thu, 10 Sep 2009 10:59:03 -0400
Message-ID: <4AA91437.1090201@gmail.com>
To: Jos de Bruijn <debruijn@inf.unibz.it>
CC: RIF <public-rif-wg@w3.org>

I was under the impression that option #3 was specifically not chosen because it 
leads to some undesirable property in BLD/OWL-DL combinations.  Also, doesn't 
BLD allow the range and domain of # to be much larger than OWL-DL does for type?

You will also have a hard time convincing me that #3 is a bug fix.

I prefer option 2, and I would include in the additional text that combinations 
that map type and subclass between BLD and OWL-2 remains a research topic.


Jos de Bruijn wrote:
> In RIF-RDF combinations, there is a one-to-one correspondence between
> rdf:type statements and # statements, and ## statements imply
> rdfs:subClassOf statements, so:
> a#b  iff a[rdf:type -> b]   and
> a##b implies a[rdf:subClassOf -> b]
> These correspondences also hold in RIF-OWL Full combinations, since
> their semantics simply extends the semantics of RIF-RDF combinations.
> Now, since the semantics of RIF-OWL DL combinations is completely
> different, these correspondences do not automatically carry over.  In
> fact, in such combinations there is no relationship between # and ##
> statements in RIF, on the one hand, and typing and subclass statements
> in OWL DL, on the other.  A minimalistic approach was taken in the
> specification of the semantics of RIF-OWL DL combinations:
> -OWL class membership statements A(?x) correspond to RIF statements
> ?x[rdf:type -> A]
> -property value statements R(?x,?y) correspond to RIF statements ?x[R -> ?y]
> There are no further correspondences between statements in OWL DL and in
> RIF.  However, some users may expect to be able to use # and ##
> statements to access OWL class membership; the document currently does
> not explain that this is not possible.
> We could do one of three things:
> 1- leave things as they are, assuming that # and ## are not of interest
> to users of RIF-OWL DL combinations
> 2- explain the use of # and ## in the document (this would certainly not
> be a substantive change, so we should not run into procedural problems)
> 3- define the semantics of # and ## in RIF-OWL DL combinations in a
> similar fashion as in RIF-RDF combinations: a one-to-one correspondence
> between # and OWL class membership statements and implication between ##
> and OWL subclassing.  Technically, this is not a problem.  In principle,
> it would be a substantive change, but we might be able to argue that it
> was a bug in the specification.
> I am fine with any of the options.  Clearly, option 1 would be least
> work for me, followed by option 3.
> Opinions?
> Best, Jos

Dr. Christopher A. Welty                    IBM Watson Research Center
+1.914.784.7055                             19 Skyline Dr.
cawelty@gmail.com                           Hawthorne, NY 10532
Received on Thursday, 10 September 2009 14:59:51 UTC

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