Re: Official OWL version outdated

Hi Holger,

this looks pretty good so far. Thanks a lot for your engagement. 
However, I'm not sure whether your utilisation of rdf:Property and 
owl:unionOf ranges that include classes as well as datatypes are really 
possible. Albeit, from the OWL 2 specs [1] I can see that there are 
definitions for ObjectUnionOf and DataUnionOf, which are somehow 
separate from each other, or? For example rNews (e.g. [2]) makes use of 
object unionOfs and datatype unionOfs, but no mixing.
Generally, you could add rdf:Property to all properties and rdfs:Class 
to all classes for "backward" compatibility (this is one of my personal 
preferences when modelling ontologies ;) ).

Cheers,


Bo


[1] http://www.w3.org/TR/2012/REC-owl2-direct-semantics-20121211/
[2] http://dev.iptc.org/files/rNews/rnews_1.0_draft3.ttl


On 5/17/2013 2:00 AM, Holger Knublauch wrote:
> Ok, I have updated the ontology as discussed - a few properties now have
> mixed ranges allowing both strings or object values, using owl:unionOf.
>
> The "single-range" version is still available as an alternative for
> those who prefer that.
>
>      http://topbraid.org/schema/
>
> Cheers
> Holger
>
>
>
> On 5/17/2013 5:31, Bo Ferri wrote:
>> Hi Holger,
>>
>> On 5/16/2013 12:10 AM, Holger Knublauch wrote:
>>> Hi Bo,
>>>
>>> thanks for your feedback.
>>>
>>> On 5/16/2013 4:56, Bo Ferri wrote:
>>>> Hi Holger,
>>>>
>>>> thanks a lot for providing this well-thoughtout schema.org to proper
>>>> RDF(S) mapping. Good work! I really endorse the mappings for the
>>>> schema/ontological terms that make use of the well known terms from
>>>> OWL and RDFS (instead of schema:Class etc.).
>>>> However, I'm wondering why you've introduced a new name space
>>>> 'schemax' to create new classes, whose ranges could also be modelled
>>>> via owl:unionOf, or?
>>>
>>> Yes I agree this isn't perfect and that's also the main reason why I
>>> marked the current version as "experimental". I would like to get more
>>> feedback on this.
>>>
>>> The main reason for just having a single range with named union classes
>>> is that many tools (including some of our own) wouldn't know what type
>>> of widget to display and how to best allow users to select values.
>>
>> Yes, okay. You made the point. So one has to decide between defacto
>> best practice ontology design and "real world" practical
>> applicability. I'm not sure, however, I think since popular ontologies
>> such as GoodRelations are also doing it this way, there must be a
>> practical solution to implement it with a satisfiable UX, or? Albeit,
>> I guess you are looking for a rather generic approach here ... where
>> it might get a bit more complicated ;)
>>
>>> This
>>> problem is especially obvious for mixed properties that allow xsd:string
>>> or objects.
>>>
>>> I will rename the current version (with the single range) and change the
>>> converter to use owl:unionOf ranges, then replace the version to use
>>> that convention. Then people have the choice which range convention they
>>> use.
>>
>> coolo!
>>
>>>
>>> Question: Some properties either allow objects or xsd:string values.
>>> Shall I leave those in tact or shall I suppress the xsd:string choice?
>>> If I leave them in I would need to turn them into rdf:Properties. I have
>>> not seen properties that have such a mixed union anywhere, but I guess
>>> it would be more correct to preserve them. Another idea would be to
>>> introduce different properties for the string part, e.g.
>>> schema:xy-string, but this would introduce different URIs. Please let me
>>> know your thoughts.
>>
>> I would endorse the rather generic, not OWL-DL compatible way by
>> utilising rdf:Property for relationships that could be datatype or
>> object properties. However, I know that this a decision against OWL-DL
>> (see also this discussion [1]). Two properties, which bare the same
>> meaning, "only" for OWL-DL compatibility will confuse the common user
>> of the vocabulary. I know that one could also implement OWL property
>> chain axioms or similar mechanism, but I guess that this would be a
>> bit against the nature of schema.org (which is nowadays already to big
>> to grasp for the common web developer (re. number of types etc.) - but
>> this is another topic ... ;) ).
>>
>> Cheers,
>>
>>
>> Bo
>>
>>
>> [1]
>> http://answers.semanticweb.com/questions/1367/restrictions-on-rdfproperty

Received on Friday, 17 May 2013 22:43:26 UTC