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Re: Nested supportedProperty

From: Holger Knublauch <holger@topquadrant.com>
Date: Mon, 15 Dec 2014 09:09:19 +1000
Message-ID: <548E189F.4060002@topquadrant.com>
To: public-hydra@w3.org
On 12/15/2014 5:44, Markus Lanthaler wrote:
> At the moment we can't really. We need to find a solution for this or, 
> if we are lucky, someone else will for us. The new RDF Data Shapes WG 
> works on exactly this. Unfortunately I'm not up to date with their 
> work but Holger (CC'ed) is quite active in that group and may have a 
> couple of minutes to give us a status update. 

The Shapes group is still in its early stages - we are about to finish 
(or freeze) the User Stories which are input to the Requirements which 
we have started collecting. It is hard to say how long that phase will 
take; I certainly hope this can be covered in January and we have the 
first technical proposals shortly after that. But who knows...

The topic of nested (or context-sensitive) property definitions has come 
up in the group as well, and it will almost certainly be covered by the 
resulting standard. For example, the Resource Shapes 2.0 language, which 
is one of the inputs to the WG, has a system property :valueShape [1] 
that is linking a :Property with additional constraints for its values. 
This is similar to owl:allValuesFrom in that it allows you to use nested 
(blank) nodes that go various hops deep from the starting point.

So although I cannot speak on behalf of the WG, I believe this topic 
will be covered by the new shapes language, and we will hopefully come 
up with something that can be plugged directly into Hydra and similar 
frameworks.

On the more general topic of properties being global or scoped to 
classes, I believe the schema.org people followed the concepts explored 
by RDF Schema (with variations of global range and domain definitions), 
yet I do not believe there are strong reasons for defining property 
semantics this way. I believe it would be more helpful to align the 
schema.org model with traditional object-oriented modeling, where a 
property would be attached to a class. This resolves some of the 
problems with overlapping domains/ranges. For example what would happen 
if a property has two rangeIncludes and two domainIncludes - which 
combinations are really valid? If you scope a property declaration to 
the context of a class, this issue is solved much clearer.

HTH
Holger


[1] http://www.w3.org/Submission/2014/SUBM-shapes-20140211/#valueShape
Received on Sunday, 14 December 2014 23:12:22 UTC

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