From: Benjamin Grosof (bgrosof@mit.edu)
Date: 10/07/03
Hi folks, Some quick comments: - good first cut overall - thanks Mike! - the expressiveness limitations of current DLP include prohibition of existentials or min-cardinality in a rule head, and correspondingly in a DL subsumption axiom's superclass expression (and a similar dual/equivalent prohibition of universals or max-cardinality in the rule body / DL-subclass). See the DLP paper for details and discussion. - tools under development include SweetOnto (OWL -> RuleML V0.8) developed by Boris Motik et al, based on the DLP paper. - we should augment and strengthen the warning a bit to explain that restricting to DLP will ensure compatibility with extending expressively to LP with NAF/courteous/nonmon and/or with procedural attachments (e.g., Situated Courteous LP) cf. currently commercially important (CCI) rule systems, but using the above LP-inexpressible OWL features (existentials etc.) will likely/possibly cause significant practical problems wrt such compatibility - we should clarify the warning to include both (and distinguish between) uses/users oriented towards extending OWL and uses/users oriented towards extending CCI/LP rule systems cf. more expressive RuleML. I'll aim to do a proper editing job soon but probably won't be able to get to it today (pretty busy in a happy way with some family stuff...). Benjamin >X-Sieve: CMU Sieve 2.2 >Delivered-To: joint-committee-outgoing@daml.org >X-Original-To: joint-committee@daml.org >Delivered-To: joint-committee@daml.org >To: joint-committee@daml.org >Subject: warning label >Date: Sun, 05 Oct 2003 15:40:48 -0700 >From: Mike Dean <mdean@bbn.com> >Sender: owner-joint-committee@wrath.daml.org >X-Spam-Score: 2.4 >X-Spam-Level: ** (2.4) >X-Spam-Flag: NO >X-Scanned-By: MIMEDefang 2.28 (www . roaringpenguin . com / mimedefang) > >As I promised during Tuesday's telecon, here's the first >draft of a "warning label" intended as a new section in [1]. >Additions, corrections, and other suggestions are welcome. > > Mike > >[1] http://www.cs.man.ac.uk/~horrocks/DAML/Rules/ > > >6.0 Usage Suggestions > >At least in the near term until OWL reasoners begin to >support OWL Rules directly, users who want to maximize >interoperability with existing rule engines and OWL >ontologies encoded in RDF/XML may want to limit their >classAtoms to use named classes defined in the same OWL XML >file or external OWL XML or RDF/XML documents, e.g. use > > <owlx:classAtom> > <owlx:Class owlx:name="#PhysicianChild"/> > <owlx:Variable owlx:name="x1"/> > </owlx:classAtom> > >with > > <owlx:Class owlx:name="PhysicianChild"> > <owlx:IntersectionOf> > <owlx:Class owlx:name="#Person"/> > <owlx:ObjectRestriction owlx:property="#hasParent"/> > <owlx:someValuesFrom owlx:class="#Physician"/> > </owlx:ObjectRestriction> > </owlx:IntersectionOf> > </owlx:Class> > >rather than > > <owlx:classAtom> > <owlx:Class owlx:name="PhysicianChild"> > <owlx:IntersectionOf> > <owlx:Class owlx:name="#Person"/> > <owlx:ObjectRestriction owlx:property="#hasParent"> > <owlx:someValuesFrom owlx:class="#Physician"/> > </owlx:ObjectRestriction> > </owlx:IntersectionOf> > </owlx:Class> > <owlx:Variable owlx:name="x1"/> > </owlx:classAtom> > >as this allows simpler translation of atoms into other rule >formats. > >Users anticipating use of their rules with prioritized >conflict resolution, defaults, procedural attachments, or >other advanced features of rule engines based on Logic >Programming may want to limit their classAtoms to use named >classes within the expressiveness of Description Logic >Programs [Grosof 2003]. This limits [Benjamin fill in >here]. > >An example of an OWL class outside the expressiveness of >Description Logic Programs is > > <owlx:Class owlx:name="Orphan"> > <owlx:IntersectionOf> > <owlx:Class rdf:name="#Person"/> > <owlx:ObjectRestriction owlx:property="#hasParent"/> > <owlx:allValuesFrom owlx:class="#Deceased"/> > </owlx:ObjectRestriction> > </owlx:IntersectionOf> > </owlx:Class> > >because of the use of owl:allValuesFrom. Use of such a >class within a classAtom may cause difficulties in future >versions of OWL Rules. > >Development of theoretical foundations and algorithms to >more fully combine the results of Description Logic and >Logic Programming is an active area of research. OWL Rules >is expected to grow as such research comes to fruition. > >Tools to convert between OWL Rules and RuleML 0.8 [RuleML] are >being developed. > > >[Grosof03] > Description Logic Programs: Combining Logic > Programs with Description Logic. Benjamin Grosof, > Ian Horrocks, Raphael Volz, Stefan Decker. Proc. > WWW2003, Budapest, May 2003. > http://www2003.org/cdrom/papers/refereed/p117/p117-grosof.html > >[RuleML] > http://www.ruleml.org ________________________________________________________________________________________________ Prof. Benjamin Grosof Web Technologies for E-Commerce, Business Policies, E-Contracting, Rules, XML, Agents, Semantic Web Services MIT Sloan School of Management, Information Technology group http://ebusiness.mit.edu/bgrosof or http://www.mit.edu/~bgrosof
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