Re: [dxwg] Relax global domain axioms on many dcat properties

I've just looked through the current DCAT vocabulary, seeing if there are any domain/range declarations that look potentially restrictive. I found very few things to worry about. That is, the ones that are present almost all seem to be entirely untroublesome. For example, it seems to me that declaring the range of dcat:distribution as dcat:Distribution is entirely sensible. Many of the properties have a domain of dcat:Dataset,  dcat:Catalog or dcat:Distribution - and they don't look wrong.

Where there might be room for change - by which I mean relaxation - is in the ranges of 
dcat:contactPoint (v:Kind)
dcat:landingPage (foaf:Document)
dcat:mediaType (dct:MediaTypeOrExtent)

I'm not advocating relaxation of these, just saying that these are the only ones that are currently defined that look like potential candidates for discussion. My point was only that if DCAT declares domains and ranges that can be shown to have been harmful or that are widely ignored, OK, relax them. And, in general, only apply domains and ranges where they actually help clarify the model, otherwise, leave it open. I'm not advocating relaxing rules for the sake of it.

Add in the properties that take skos:Concept as a range to my short list and I realise that the thing they have in common is that they're all properties in the dcat namespace that declare a range outside of it - and that may or may not be how they're used in the wild.

As @makxdekkers says, DCAT is used widely already. The main task is to add in the terms that usage has shown are lacking. In doing that, and in addressing new use cases, one might find a reason to add in an extra layer of semantics - no problem with that as the SOSA/SSN experience shows. 

And as @arminhaller points out, domains and ranges aren't actually restrictions, rather they can allow computers to infer the type of resource. So if you see dcat:landingPage, you can infer that its object is a foaf:Document - and Web pages certainly fit that description.

Where semantics might get more tricky, as recent discussions show, is around things like PROV. That seems more like the area where an additional graph might be handy.

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Received on Tuesday, 20 February 2018 08:31:42 UTC