Re: RDF Schema abstract

On Nov 28, 2013, at 4:49 AM, Dan Brickley <danbri@google.com> wrote:

> On 28 November 2013 10:12, Guus Schreiber <guus.schreiber@vu.nl> wrote:
>> 
>> 
>> On 28-11-13 06:00, Pat Hayes wrote:
> 
>>>> RDF Schema provides a simple data-modelling vocabulary for RDF data.
>>>> Other publications, including SKOS [ ] and the W3C Recommendation OWL2 [ ],
>>>> define more elaborate data models which extend RDFS in various ways.
>> 
>> 
>> I prefer to leave "simple" out. RDFS is not simple, mainly because it has
>> the notion of sub-property, which is a powerful mechanism not present in most
>> data-modelling languages (UML has the notion of "Association Class", but that
>> is less flexible).
> 
> It might still be 'simple'; this just shows some awkwardness in
> calling it a 'simple data modeling' language, perhaps? e.g. It might
> be a simple language for data modeling, even if not 'simple' by
> data-modeling language standards?
> 
>> Also, "simple" has a subjective connotation.
> 
> Clearly :)
> 
> As with RDFa there is quite a different experience for implementors
> versus publishers/authors. If I'm just writing claims using RDF/S,
> it's straightforward enough to understand that something like
> dc:creator refines the more general super-property dc:contributor, and
> that if I say that someone is the dc:creator of something it wouldn't
> make much sense to simultaneously deny that they were also a
> dc:contributor. Authors will need help understanding how domain/range
> interact here, but the basic idea is straightforward.
> 
> For someone writing an inference engine or trying to optimize database
> indices for common query patterns, they might plausibly object to the
> use of 'simple' :)

Well actually it was thinking about the inferences needed, and mentally contrasting that with what is needed for OWL2, that suggested the word "simple" to me. You can implement a complete RDFS reasoner using the entailment patterns in the spec, applied blindly to exhaustion using a simple one-way unifier, and it will run quite effectively on most published RDFS, but you need be a description-logic specialist to even start implementing a semantic tableau OWL reasoner. 

But I won't defend the use of "simple" if Guus wants to remove it. 

Pat

> Similarly, the publisher experience of RDFa and
> Microdata is pretty similar, whereas the parser writers have
> significantly more pain with RDFa, to support its various additional
> idioms.
> 
> Dan
> 

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Received on Friday, 29 November 2013 18:05:34 UTC