- From: Holger Knublauch <holger@topquadrant.com>
- Date: Sat, 25 Oct 2014 14:02:02 +1000
- To: public-data-shapes-wg@w3.org
Hi Peter, thanks for your paper. It shows that it is possible to reuse the OWL vocabulary for closed-world constraint checking. I believe there is little disagreement that this is feasible in theory and that owl:Restrictions cover some of the requirements identified in the catalog, esp cardinality and range restrictions. In fact, the closed-world semantics are probably how a lot of people already use OWL anyway and some ontology editors have already used owl:maxCardinality info to limit user input. However, OWL only covers a subset of the overall requirements and could therefore IMHO only be one aspect of a larger solution. In the implementation section you briefly mention: "(Recent work at Mannheim implements OWL descriptions as constraints using a similar approach.)" I would like to hear your thoughts about this approach. I assume you are referring to the work announced by Thomas Bosch to the previous mailing list http://lists.w3.org/Archives/Public/public-rdf-shapes/2014Jul/0250.html This is a SPIN constraint library that scans the input graph at usages of the OWL namespace and reports violations against the closed world interpretation, very similar to what you describe in your paper and to what other OWL closed-world implementations such as Stardog ICV do. All that is needed to activate this type of constraint checking for a given graph is to mark that graph, e.g. with a spin:imports (or ic:imports) triple. Basically what this is outlining is that if something like SPIN would be standardized, then a SPIN constraints library can be published that knows how to interpret OWL restrictions etc. However, people would have the freedom to mix and match OWL with other vocabularies, without being limited by the design choices of a language that was driven by the computational theory of Description Logics. If someone wants to have their graph interpreted with OWL closed-world semantics, they would only need to add a triple my:Ontology spin:imports <http://w3.org/something/owl> and a generic SPIN engine can figure out the rest from there, without requiring any hard-coded knowledge about OWL. This would in principle allow users to reuse existing OWL ontology definitions. Another question I have is how you would address the issue of redefining the semantics of the OWL vocabulary that already has numerous books and papers written about it, all explaining the details of a rather different open-world semantics. That issue could suggest that a fresh start with a new vocabulary (such as Shapes) might be a better option than confusing the market with a semantically overloaded vocabulary. Thanks, Holger On 10/23/2014 16:10, Peter F. Patel-Schneider wrote: > I suggested that anyone who is going to present technical stuff at the > WF F2F meeting next week send out something about the stuff beforehand. > > I am here covering my marker. (In a certain sense - this is an > academic paper, not a manual, although this stuff is actually > implemented in Stardog ICV, more or less.) > > Questions welcome. > > peter > > >
Received on Saturday, 25 October 2014 04:04:30 UTC