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Re: How to avoid that collections "break" relationships

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Sat, 12 Apr 2014 13:32:14 -0700
Message-ID: <5349A2CE.9030502@gmail.com>
To: Ruben Verborgh <ruben.verborgh@ugent.be>
CC: Markus Lanthaler <markus.lanthaler@gmx.net>, Pat Hayes <phayes@ihmc.us>, Linked Data community <public-lod@w3.org>, W3C Web Schemas Task Force <public-vocabs@w3.org>, Dan Brickley <danbri@danbri.org>

On 04/09/2014 12:57 AM, Ruben Verborgh wrote:
>> What then is RDF for you?
> The Resource Description Framework.
> It is a framework to describe resources,
> and this includes predicates.
> Anybody can define predicates the way they want,
> otherwise RDF is useless to express semantics.


Ok, I describe ex:BaseballPlayer as
ex:BaseballPlayer owl:equivalentClass _:x .
_:x owl:intersectionOf ( ex:Person  [ owl:onProperty ex:plays; owl:hasValue 
ex:Baseball ] )

Is this RDF?  Should all consumers of RDF understand all of this?
>> For example, do you consider N3 to be RDF?
> No, quantification is not part of RDF.

Why not?  I could certainly define an encoding of quanfification in RDF and 
use it to define predicates.
>
>> Can predicates have non-local effects?
> A predicate indicates a relationship between an object and a subject.
> What this relationship means is described in the ontology to which the predicate belongs.
>
> Predicates may not influence non-related triples,
> however, other triples might be influenced through a cascade of relations.

Why not?  I can define predicates however I want, after all?
>
>> What does using owl:differentFrom in RDF commit you to?
> It says that two things are different.
> Clients that can interpret this predicate can apply its meaning.
> This application does not change the model.

What model?  Do  you mean that all you care about is the abstract syntax?  
What about rdf:type?  What about rdfs:domain?  Do all consumers of RDF need to 
commit to the standard meaning of these predicates?
>
>> To me, what RDF does not do is just as important and what it does do.  This means that RDF captures only the RDF bit of the meaning of predicates - the rest of their meaning remains inaccessible from RDF.  Any attempt to go beyond this is … going beyond RDF and it is very important do realize this.
> RDF is just the model. Giving a predicate meaning is not extending the model.


How so?  What else is giving a predicate meaning besides extending the  model?
>
> Best,
>
> Ruben

I am really struggling to understand your view of RDF.


peter
Received on Saturday, 12 April 2014 20:32:46 UTC

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