Re: Exactly one element in a RDFS class

Writing a SPARQL construct query to determine which classes are de facto 
singletons is not possible, as far as I can tell.  There are very many ways 
for an OWL class to be a de facto singleton beside being equivalent to a 
singleton set.  For example, the class could be equivalent to the intersection 
of two sets that have single member in common.

It is also possible for non-class axioms to produce de facto singleton OWL 
classes.  For example what might look to be a doubleton could be turned into a 
singleton by a sameAs.

In general, SPARQL is not powerful enough to analyze OWL classes.

peter


On 11/17/2014 07:32 AM, Aldo Gangemi wrote:
> I think you need to preprocess your data with a sparql construct query to find
> out what classes are de facto singletons, and to assign those classes a
> punning type such as :Singleton. After that, you can use Ada.
> Best
> Aldo
>
> On Monday, November 17, 2014, Peter F. Patel-Schneider <pfpschneider@gmail.com
> <mailto:pfpschneider@gmail.com>> wrote:
>
>     I'm having a very hard time coming up with any overlap between this
>     discussion and anything that might happen in the RDF data shapes working
>     group.  The working group is about detecting explicit information in RDF
>     documents---this discussion is about how to create singleton classes, and
>     maybe how to detect such singleton classes in an RDF encoding.
>
>     That said, SPARQL is used in several of the technologies being
>     investigated by the working group and it is probably possible to write a
>     SPARQL query to detect a singleton class in the RDF encoding of OWL, but
>     this doesn't provide any true commonality.
>
>     peter
>
>
>     On 11/17/2014 01:50 AM, Phil Archer wrote:
>
>         This sort of debate is exactly the kind of thing that is behind the newly
>         formed RDF Data Shapes working group. Its charter includes pointers to
>         a bunch
>         of existing work in this area that may be useful.
>
>         See http://www.w3.org/2014/data-__shapes/
>         <http://www.w3.org/2014/data-shapes/>
>
>         Cheers
>
>         Phil.
>
>
>         On 16/11/2014 23:03, Pavel Klinov wrote:
>
>             There's no simpler encoding. Nominals is the only feature in OWL 2
>             which lets you say that a class has a single instance. And it has a
>             unique serialization in RDF.
>
>             I don't think querying for this particular syntactic construct is
>             complex.
>
>             However, writing RDF queries for OWL ontologies serialized in RDF (be
>             that SPARQL or other RDF graph matching language) is usually not a
>             great idea. You'll often have to deal with specifics of the RDF
>             serialization which is complex for many OWL constructs (see [1])
>
>             Cheers,
>             Pavel
>
>             [1] http://www.w3.org/TR/owl2-__mapping-to-rdf/
>             <http://www.w3.org/TR/owl2-mapping-to-rdf/>
>
>             On Sun, Nov 16, 2014 at 11:35 PM, Victor Porton <porton@narod.ru>
>             wrote:
>
>                 Your solution has the same problem as Patrick Logan's one.
>                 (See my previous
>                 email.) In fact your solution is the same as Patrick Logan's one.
>
>                 17.11.2014, 00:28, "Pavel Klinov" <pavel.klinov@uni-ulm.de>:
>
>                     Sorry, my previous email got sent too soon.
>
>                     Here's the link to the right place in the OWL 2 spec:
>
>                     http://www.w3.org/TR/owl2-__syntax/#Enumeration_of___Individuals
>                     <http://www.w3.org/TR/owl2-syntax/#Enumeration_of_Individuals>
>
>                     Cheers,
>                     Pavel
>
>                     On Sun, Nov 16, 2014 at 10:52 PM, Victor Porton
>                     <porton@narod.ru> wrote:
>
>                            Is there any advise on how to code in RDFS or OWL
>                         the following statement?
>
>                            "The class X has exactly one element."
>
>                            --
>                            Victor Porton - http://portonvictor.org
>
>
>                 --
>                 Victor Porton - http://portonvictor.org
>
>
>
>
>

Received on Monday, 17 November 2014 15:49:45 UTC