- From: Michael Schneider <schneid@fzi.de>
- Date: Sun, 14 Dec 2008 12:04:06 +0100
- To: <public-owl-wg@w3.org>
- Message-ID: <0EF30CAA69519C4CB91D01481AEA06A0EA6CB9@judith.fzi.de>
Hi! While trying to align the formulae in the RDF-Based Semantics with those in the Direct Semantics, a few questions arose about n-ary dataranges (the "n-ary stub"), where I am not sure whether OWL 2 Full is currently in line with OWL 2 DL. The Direct Semantics states in Section 2.2.2 [1]: "Data ranges, however, can be n-ary, [...] An n-ary data range DR is interpreted as an n-ary relation (DR)DT over ?D." Now, in the following Table 3, I can see that complements are really defined for n-ary dataranges, not just for unary ones: ComplementOf( DR ) | (?D)^n \ (DR)^DT where n is the arity of DR * My first question is: Is this really intended? Do we want/need complements of n-ary dataranges? * Second, I don't know what is the situation for intersections and unions of dataranges (also Table 3). Are they supposed to be defined for n-ary dataranges, too? I don't remember any discussion on this, when we talked about the addition of these features (before and at F2F4). But it would look odd, IMHO, if only complements are allowed for n-aries, but not the other boolean constructs. I would expect that either all or none of the boolean constructs can be used together with n-ary dataranges. * Third: Dataranges (marked by "DR") are also mentioned at other places of the spec. For example, data-QCRs [2] and domain/range axioms [3] are defined for data ranges, not for data types. Now I wonder: From the definitions of these language constructs, it doesn't appear that they can be used with n-ary dataranges, because the instances of the dataranges mentioned there are values of data properties, hence ordinary datatype values. But this should then be made a bit more clear, because it seems to be in odd with Section 2.2.2 [1], which says that dataranges can be n-ary. Cheers, Michael [1] http://www.w3.org/2007/OWL/wiki/Direct_Semantics#Data_Ranges [2] http://www.w3.org/2007/OWL/wiki/Direct_Semantics#Class_Expressions [3] http://www.w3.org/2007/OWL/wiki/Direct_Semantics#Data_Property_Expression_Ax ioms -- 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 Sunday, 14 December 2008 11:04:48 UTC