Re: Can Shapes always be Classes?

On 11/7/2014 12:05, Eric Prud'hommeaux wrote:
> * Holger Knublauch <holger@topquadrant.com> [2014-11-07 08:28+1000]
>> This context-sensitive constraint would be attached to Issue
>> (because it is really issue-specific, and does not apply to all
>> Person instances).
> Could you mock that up using the data and schema earlier in this
> thread?

I believe I already did here:

http://lists.w3.org/Archives/Public/public-data-shapes-wg/2014Nov/0044.html

and (with possible extensions) here:

http://lists.w3.org/Archives/Public/public-data-shapes-wg/2014Nov/0075.html

> I ask because the uses of SPIN templates that I've seen have
> all involved rdfs:range inference applied globally to a predicate
> while common practice (at least among the OWL community) is to keep
> predicates as reusable as possible by constraining their use in
> particular contexts with onProperty restrictions.

No. I am not sure which SPIN templates you have seen, but there is zero 
reliance on rdfs:range or inferencing in general in SPIN. I must 
misunderstand what you mean.

I would actually consider global domains/ranges as an anti-pattern: all 
object-oriented systems allow the reuse of property names and scope 
those properties relative to a class, not globally. schema.org is a good 
example of that, and the problems of enforcing global ranges/domains. I 
had given examples of how SPIN can represent localized Resource Shapes 
and even owl:allValuesFrom using SPIN templates. The fact that SPIN uses 
the class hierarchy as its basic evaluation structure makes it natural 
to attach range constraints to a branch of the class tree only.

>>                     Most other constraints on Person would remain
>> globally, so one would only need to cover the small differences that
>> are Issue-specific (and the default constraints get owl:imported
>> from another file). So the delta that is actually needed here is
>> quite small. And is this even a real use case, or a constructed
>> example? Why should not every user of the Issue tracker have an
>> email address?
> Just about any time you see re-used types, there is a strong
> possibility that different people will have different restrictions on
> their use.

Yes, and that's not a bug but a feature. I also wonder how the situation 
would change with stand-alone Shapes. In ShEx someone would publish an 
ontology together with a set of Shapes, and others can chose to reuse or 
ignore those Shapes. In OWL or SPIN they would just use named graph, and 
we usually recommend separating the schema itself (just the classes and 
properties) from their constraints into separate named graphs/files. 
People can then chose what they want to owl:import. Yet all these 
semantic variations can be published on a web server. I am obviously not 
talking about "The Semantic Web" here, where everything would be 
union'ed together - this is unrealistic to begin with.

HTH
Holger

Received on Friday, 7 November 2014 02:50:06 UTC