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OWL 2 RL unification proposal: My comments

From: Michael Schneider <schneid@fzi.de>
Date: Wed, 3 Sep 2008 15:35:30 +0200
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A0B98777@judith.fzi.de>
To: "Ian Horrocks" <ian.horrocks@comlab.ox.ac.uk>, "Boris Motik" <boris.motik@comlab.ox.ac.uk>, <public-owl-wg@w3.org>
Hi!

Just before the poll on ISSUE-131, I managed to read the proposal for a
unified OWL 2 RL language in

  <http://www.w3.org/2007/OWL/wiki/Profiles#OWL_2_RL>

Just a few comments.

* 4.2.1 (Entities)

Just for my own curiosity: Why are certain datatypes such as
xsd:negativeInteger or xsd:nonPositiveInteger disallowed, while e.g.
xsd:nonNegativeInteger is supported (same section)?

* 4.3. (Reasoning using Rules)

  """
  The implications are given as 
  universally quantified first-order implications
  """

Duplicate use of the term "implications". Should perhaps be

  The /rules/ are given as ...

* After Table 8:

  """
  An OWL 2 RL/RDF implementation can 
  add these triples and entailment rules as necessary
  """

Probably better is the use of RFC 2119 terminology:

  An OWL 2 RL/RDF implementation /MAY/ ...

* A non-editorial point, and a bit more controversial, I guess (related to
ISSUE-116): Having a second sentence of this "MAY" form about additional
axiomatic triples for the OWL vocabulary being used in the rules would make
me happy. :) 

It's pretty clear that, if the RDFS axiomatic triples don't hurt, then
additional OWL axiomatic triples wouldn't hurt, either. And the Full
semantics provides guidance, how these additional axiomatic triples would
look like in each case. So no need to list all these triples explicitly in
the profiles document. Just a pointer to the Full semantics, in particular
tables 4.3 and 4.4, should be sufficient. People, who are really interested
in those axiomatic triples would need to take the burden on them to
translate the entries there into the triples (actually: ground rules without
an antecedent), but that's not hard to achieve. 

For example, the entry for owl:equivalentClass in table 4.4 is

  URI U = "owl:equivalentClass"
  IS(U) in IP
  IEXT(IS(U)) subset IC x IC

which can be translated into the following axiomatic triples

  owl:equivalentClass rdf:type rdf:Property
  owl:equivalentClass rdfs:domain rdfs:Class  	// or owl:Class
  owl:equivalentClass rdfs:range rdfs:Class


Cheers,
Michael

--
Dipl.-Inform. Michael Schneider
FZI Forschungszentrum Informatik Karlsruhe
Abtl. Information Process Engineering (IPE)
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Fax  : +49-721-9654-727
Email: Michael.Schneider@fzi.de
Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555

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Received on Wednesday, 3 September 2008 13:36:11 UTC

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