W3C home > Mailing lists > Public > semantic-web@w3.org > February 2009

Re: Extending RDFS, property-classes

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Tue, 10 Feb 2009 09:01:54 -0500
Message-ID: <29af5e2d0902100601r154490c7q3ad199188e975188@mail.gmail.com>
To: Jiri Prochazka <ojirio@gmail.com>
Cc: semantic-web@w3.org

On Tue, Feb 10, 2009 at 7:16 AM, Jiri Prochazka <ojirio@gmail.com> wrote:
> Hi Alan,
>
> I have seen that specification before, however I was unable to
> understand almost anything from it, especially the functional syntax
> confuses me,

Noted. There will soon be inline translations in a variety of
syntaxes, including turtle.

> but from the 2nd link I understand something... and if I am
> right, it is the mechanism for expressing information about triples,
> however it doesn't solve the problem of being able to infer between the
> reified class and the property...

Could you give me an example of an inference that you would want to
obtain - Ideally in the form of a realistic use case? I find it easier
to evaluate the larger situation than to look so narrowly.

> If it does, it would be really helpful if you could provide the example
> of this mapping on the tag ontology (in turtle please)...

FYI, there is a converter between all the syntaxes (subject to usual
caveats about being an early implementation) at
http://owl.cs.manchester.ac.uk/converter/

But yes, I can respond in turtle.


> Anyway thanks to my vocabulary it should be possible to map the
> properties reified to classes to OWL annotations...right?

I favor an approach that does as little "mapping" as possible, instead
using the primary vocabulary terms. In my experience its not a given
that mapping is well understood and implementable by clients.

> As I said, I don't understand OWL2 much...

Understood. I will try to help.

> The purpose of this ontology is exactly what Cygri said in his reply to
> Richard Newman:
> "technique for mapping between those "high-detail" and "low-detail"
> vocabularies. At the moment, we'd have to use rules for that, because
> neither RDFS nor OWL can express that sort of mapping."
>
> Kind regards,
> Jiri Prochazka (irc Anchakor)
>
> Alan Ruttenberg wrote:
>> Hello Jiri,
>>
>> The OWL 2 Specification, now in last call, has extended facilities for
>> annotation. You might want to have a look..
>>
>> The relevant sections are in the Syntax specification and the RDF Mapping.
>>
>> http://www.w3.org/TR/2008/WD-owl2-syntax-20081202/#Annotations
>> http://www.w3.org/TR/2008/WD-owl2-mapping-to-rdf-20081202/#Translation_of_Annotations
>>
>> If you aren't familiar with functional syntax for OWL (it's relatively
>> new) the thing to know is that it gives a more concise way to write
>> OWL statements but is mapped to RDF/XML for exchange. We do intend to
>> enhance that document so the examples are in RDF as well, but it is
>> work in progress.
>>
>> Briefly the facility allows for annotation of any entity, including
>> axioms such those a simple triple might encode - called a
>> PropertyAssertion in the syntax document, but also ones that have a
>> more complex RDF encoding, such as an OWL restriction or to annotate
>> an annotation itself.
>>
>> Even if you are not using much OWL in your application, you could use
>> the OWL vocabulary and mapping and vocabulary to write your
>> annotations.
>>
>> Regards,
>> Alan
>>
>> On Mon, Feb 9, 2009 at 3:54 PM, Jiri Prochazka <ojirio@gmail.com> wrote:
>>> Hi,
>>> inspired with recent discussion with Richard Newman ("RDF vocabulary
>>> scope guidelines, promoting properties to classes  - property
>>> identifiers") I have a suggestion to make.
>>>
>>> RDF has no way of identifying predicate (property) uses (triples), which
>>> only restricts information about them to:
>>> 1) about what they state something (domain)
>>> 2) what they state about something (range)
>>>
>>> This is insufficient for number of uses, take for example Richards tag
>>> ontology: http://www.holygoat.co.uk/projects/tags/
>>>
>>> Apart from properties tag:taggedWithTag and tag:isTagOf, it defines
>>> class tag:Tagging, which extends them (it is these properties promoted
>>> to class), allowing more information about the relation to be expressed.
>>>
>>> This is a good thing, but unfortunately there is no link between the
>>> properties and the class, which makes the data tagged with the
>>> properties and the data tagged with the class, like they each used
>>> different non-interlinked vocabularies...
>>>
>>> I suggest to develop an extension to the vocabulary describing
>>> vocabularies (RDFS, OWL), so vocabulary designers could specify the link
>>>  and inferencing engines could work with it...
>>>
>>> The vocabulary should map the property to the property-class since the
>>> expressiveness of the property is subset of the one of the property-class.
>>>
>>> Basically the vocabulary draft should be:
>>>
>>> :isPromotedProperty a rdf:Property ;
>>>        rdfs:domain rdfs:Class ;
>>>        rdfs:range rdf:Property .
>>> # But also it should use it's own philosophy on itself:
>>> :PropertyPromotion a rdfs:Class ;
>>>        rdfs:subClassOf rdf:Property .   (really not sure here)
>>> :promotionOf a rdf:Property ;
>>>        rdfs:domain :PropertyPromotion ;
>>>        rdfs:range rdf:Property .
>>> :hasDomain a rdf:Property ;
>>>        rdfs:subPropertyOf rdfs:domain ;   (really not sure here)
>>>        rdfs:domain :PropertyPromotion .
>>> :hasRange a rdf:Property ;
>>>        rdfs:subPropertyOf rdfs:range ;   (really not sure here)
>>>        rdfs:domain :PropertyPromotion .
>>> # And final craziness:
>>> :PropertyPromotion a :PropertyPromotion ;
>>>        :promotionOf :isPromotedProperty ;
>>>        :hasDomain rdfs:Class ;
>>>        :hasRange rdf:Property .
>>> :PropertyPromotion :isPromotedProperty :isPromotedProperty .
>>>
>>> Important is that the conversion can be done both directions.
>>>
>>> Please comment on this proposal.
>>> If at least some people think this is a good idea, I could work on the
>>> vocabulary and rdfs:label and rdfs:comment it and publish it, however in
>>> corner of my mind I think it would need backing of W3C to be of any use
>>> (as all vocabulary describing vocabularies).
>>>
>>> Kind regards,
>>> Jiri Prochazka
>>>
>>>
>
>
Received on Tuesday, 10 February 2009 14:02:32 UTC

This archive was generated by hypermail 2.4.0 : Tuesday, 5 July 2022 08:45:10 UTC