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Re: How to avoid that collections "break" relationships

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Mon, 31 Mar 2014 10:09:09 -0700
Message-ID: <5339A135.40203@gmail.com>
To: Ruben Verborgh <ruben.verborgh@ugent.be>
CC: Markus Lanthaler <markus.lanthaler@gmx.net>, Pat Hayes <phayes@ihmc.us>, public-hydra@w3.org, Linked Data community <public-lod@w3.org>, W3C Web Schemas Task Force <public-vocabs@w3.org>, Dan Brickley <danbri@danbri.org>
If you want a hydra solution, then you should do whatever is needed to make it 
a hydra solution.

In actuality, defining things like owl:sameAs is indeed extending RDF.  
Defining things in terms of OWL connectives also goes beyond RDF. This is 
different from introducing domain predicates like foaf:friends.   (Yes, it is 
sometimes a bit hard to figure out which side of the line one is on.)

peter



On 03/31/2014 09:26 AM, Ruben Verborgh wrote:
> Peter,
>
> Please, let's get the discussion back
> to what we want to achieve in the first place.
> Right now, the solution is being evaluated
> on a dozen of other things that are not relevant.
>
> Proposal: let's discuss the whole abstract RDF container thing on public-lod@w3.org,
> and solutions to make clients work at public-hydra@w3.org.
>
> We're talking here about making clients able to get the members of something.
> Yes, they will need to interpret some properties.
> Just like an OWL reasoner needs to interpret owl:sameAs,
> a Hydra client needs to interpret hydra:member.
> That is how applications work.
>
> In no way, defining a vocabulary is extending RDF.
> RDF is a framework. I'm not adding to the framework.
> I'm proposing a simple property
>      hydra:memberOf owl:inverseProperty hydra:member.
> If you really don't like me introducing a property,
> here's an alternative way of saying the same thing:
>
>     </people/markus> foaf:knows _:x.
>     </people/markus/friends> hydra:member _:x.
>
> There you go. hydra:member was already defined,
> I'm not inventing or adding anything.
>
>> You want to depend on a particular reading of this non-RDF predicate, and have this reading trigger inferences.
> No I don't want any of that. Why do think I'd want that?
> Where did I say I want inferences? Where do I need them?
>
> Also, how could it possibly be a non-RDF predicate?
> RDF simply defines a predicate as an IRI [1].
>
>> Again making a significant addition to RDF.
> When did defining a vocabulary become adding to RDF?
>
>> Which is precisely my point.  You are using OWL, not just RDF.  If you want to do this in a way that fits in better with RDF, it would be better to add to the syntax of RDF without adding to the semantics of RDF.
> …but this has _never_ been about extending RDF in any way,
> nor has it been about only using RDF or only using OWL.
> We don't want any of that. We want:
>
> 1. Having a way for clients to find out the members of a specific collection
> 2. Not breaking the RDF model while doing so
>
> The proposed solution achieves both objectives.
>
> Best,
>
> Ruben
>
> [1] http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#dfn-predicate
Received on Monday, 31 March 2014 17:09:43 UTC

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