- From: Alan Ruttenberg <alanruttenberg@gmail.com>
- Date: Tue, 12 Aug 2008 10:34:48 -0400
- To: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
- Cc: Michael Schneider <schneid@fzi.de>, public-owl-wg Group WG <public-owl-wg@w3.org>, Ivan Herman <ivan@w3.org>, Zhe Wu <alan.wu@oracle.com>
Is the assumption that in OWL R/Full that the only way in which one determine entailments is to forward chain rules and then look in the resultant triples for it? -Alan On Aug 12, 2008, at 10:18 AM, Ian Horrocks wrote: > > Michael (and Ivan), > > I don't have any problem with axiomatic triples in principle. > However, while they may be (relatively) harmless in principle, I > worry that they could be extremely damaging from an implementation > perspective. > > Presumably, making axiomatic triples be part of OWL RL (Full) would > mean extending the rule set so that it would generate such triples. > There could be a very large (perhaps even infinite) number of such > triples. This might be a serious burden on implementations and lead > to a significant degradation in performance. > > I CCed Zhe on this in the hope that we can get a view on this from > an OWL R implementer. > > ian > > > > > > > On 11 Aug 2008, at 15:15, Michael Schneider wrote: > >> [cc'ing Ivan Hermann as the raiser of ISSUE-116.] >> >> Dear WG! >> >> At F2F3, ACTION-178 was put on me to explain my understanding of >> >> ISSUE-116: "Should Axiomatic Triples be added to OWL-R Full?" >> >> Here is my understanding, after a short explanation what axiomatic >> triples are. >> >> (A) What are axiomatic triples? >> ------------------------------- >> >> These are typical examples of axiomatic triples (taken from RDFS): >> >> (1) rdf:Property rdf:type rdfs:Class >> (2) rdf:type rdf:type rdf:Property >> >> These axiomatic triples specify the part of the universe to which >> certain URIs of the "system vocabulary" belong: 'rdf:Property' >> denotes a class, while 'rdf:type' refers to a property. >> >> Note that in RDF, there is no real distinction between the >> vocabulary specifying the language (such as 'rdf:type'), and the >> custom vocabulary used within an ontology. Axiomatic triples >> interpret the system vocabulary, by telling what's true for them >> independently of the concrete ontology, in which they are used. >> >> Axiomatic triples are defined in RDF and RDFS, and also in pD*. >> OWL 1 Full also contains lots of axiomatic triples for the OWL >> vocabulary, though they are written in a different notation there. >> >> (B) Which axiomatic triples do typically exist? >> ----------------------------------------------- >> >> Aside of type information (as in the examples (1) and (2)), RDFS >> also specifies the domain and range for all properties in the RDFS >> vocabulary, e.g.: >> >> (3) rdf:type rdfs:domain rdfs:Resource >> (4) rdf:type rdfs:range rdfs:Class >> >> (C) What is the scope of the issue? >> ----------------------------------- >> >> The main question at F2F3 was whether this issue is also about >> *additional* genuine OWL R Full axiomatic triples, or just about >> RDFS axiomatic triples. From Ivan's mail it becomes pretty clear >> that this issue includes axiomatic triples, which go beyond RDFS >> (Ivan confirmed this to me in a private mail). One of his stated >> examples is: >> >> "owl:FunctionalProperty,rdfs:subClassOf,rdf:Property" >> >> This assertion clearly does *not* exist in RDFS, since >> 'owl:FunctionalProperty' doesn't belong to the RDFS vocabulary. >> (Whether this example would be a useful axiomatic triple or not >> for OWL R Full is not a topic here.) >> >> (D) What would be the additional axiomatic triples? >> --------------------------------------------------- >> >> Defining axiomatic triples is in most times a pretty straight >> forward task. For all OWL URIs in the OWL R vocabulary the type is >> stated (Resource, Class, Property), and for properties also the >> range and domain. All axiomatic triples which I have in mind would >> follow the examples (1) to (4) above. >> >> For example, for 'owl:complementOf', I would propose the axiomatic >> triples: >> >> owl:complementOf >> rdf:type rdf:Property ; >> rdfs:domain rdfs:Class ; >> rdfs:range rdfs:Class . >> >> Since OWL 2 Full will also have axiomatic triples (the old ones >> from OWL 1 Full, and new ones for the new vocabulary), OWL R Full >> can simply take what it needs from OWL 2 Full. >> >> (E) Could additional axiomatic triples lead to problems? >> -------------------------------------------------------- >> >> I suppose that if RDFS axiomatic triples do not already lead to >> problems, then additional axiomatic triples for the OWL R >> vocabulary will not lead to problems, either. >> >> In general, I expect axiomatic triples, as long as they have the >> form given in (D), to be semantically harmless (well, mostly >> harmless :)). >> >>> From a spec'ing effort perspective, adding them is an easy task >>> (I am offering to do this, should the WG decide to add them). >> >> Regards, >> Michael >> >> -- >> Dipl.-Inform. Michael Schneider >> FZI Forschungszentrum Informatik Karlsruhe >> Abtl. Information Process Engineering (IPE) >> Tel : +49-721-9654-726 >> Fax : +49-721-9654-727 >> Email: Michael.Schneider@fzi.de >> Web : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555 >> >> FZI Forschungszentrum Informatik an der Universität Karlsruhe >> Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe >> Tel.: +49-721-9654-0, Fax: +49-721-9654-959 >> Stiftung des bürgerlichen Rechts >> Az: 14-0563.1 Regierungspräsidium Karlsruhe >> Vorstand: Rüdiger Dillmann, Michael Flor, Jivka Ovtcharova, Rudi >> Studer >> Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus >> > >
Received on Tuesday, 12 August 2008 14:35:38 UTC