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Re: Schema.org in RDF ...

From: Christopher Gutteridge <cjg@ecs.soton.ac.uk>
Date: Tue, 07 Jun 2011 10:22:43 +0100
Message-ID: <EMEW3|1fb464a00ec43924b28e05d96e564673n56AMo03cjg|ecs.soton.ac.uk|4DEDEDE3.3080602@ecs.soton.ac.uk>
To: Bernard Vatant <bernard.vatant@mondeca.com>
CC: Michael Hausenblas <michael.hausenblas@deri.org>, Linked Data community <public-lod@w3.org>
If I've understood correctly http://schema.org/Person does not in any 
way equal or equiv to foaf:person

Surely:
?foo a <http://schema.org/Person> .

is actually saying

?foo foaf:primary_topic ?person .
?person a foaf:Person .

I've said before that there's value in predicates which relate the 
primary topic of X to the primary topic of Y, as that's what people want 
to do in RDFa. When converting into more reasonable (pun intended) 
predicates, this level of indirection should be recognised.

foaf:interest already as a domain which is the page, not the URI itself. 
http://xmlns.com/foaf/spec/#term_interest -- I'm not keen on mixing them 
in one scheme -- it'll confuse people, but let people relate things 
together using their URLs and make the semantics describe that honestly.



Bernard Vatant wrote:
> Hi Michael
>
> I just repeated what some people-who-know-better around assumed  ...
> For myself I'm sure of nothing, in particular regarding the future :)
> And that's exactly why seems to me that assertions published today 
> should not preempt (possible) semantics of tomorrow, but rely on 
> semantics as they stand : http://schema.org/Person is an information 
> resource, not a rdfs:Class.
>
> In the solution I propose, whenever the event you expect happens, just 
> add owl:equivalentClass and owl:equivalentProperty to your descriptions.
> If it does not happen as you wish, nothing is broken. If people at 
> schema.org <http://schema.org> change their mind and throw away 
> everything, you get rid of the dcterms:source and your descriptions 
> stay alive and backward compatible for people in the RDF world. Et voilà.
>
> Bernard
>
> 2011/6/7 Michael Hausenblas <michael.hausenblas@deri.org 
> <mailto:michael.hausenblas@deri.org>>
>
>         Something I don't understand. If I read well all savvy
>         discussions so far, publishers behind http://schema.org URIs
>         are unlikely to ever provide any RDF description,
>
>
>     What makes you so sure about that not one day in the (near?)
>     future the Schema.org URIs will serve RDF or JSON, FWIW,
>     additionally to HTML? ;)
>
>
>     Cheers,
>            Michael
>     --
>     Dr. Michael Hausenblas, Research Fellow
>     LiDRC - Linked Data Research Centre
>     DERI - Digital Enterprise Research Institute
>     NUIG - National University of Ireland, Galway
>     Ireland, Europe
>     Tel. +353 91 495730
>     http://linkeddata.deri.ie/
>     http://sw-app.org/about.html
>
>     On 7 Jun 2011, at 08:44, Bernard Vatant wrote:
>
>         Hi all
>
>         Something I don't understand. If I read well all savvy
>         discussions so far, publishers behind http://schema.org URIs
>         are unlikely to ever provide any RDF description, so why are
>         those URIs declared as identifiers of RDFS classes in the
>         http://schema.rdfs.org/all.rdf. For all I can see,
>         http://schema.org/Person is the URI of an information
>         resource, not of a class.
>         So I would rather have expected mirroring of the schema.org
>         <http://schema.org> URIs by schema.rdfs.org
>         <http://schema.rdfs.org> URIs, the later fully dereferencable
>         proper RDFS classes expliciting the semantics of the former,
>         while keeping the reference to the source in some
>         dcterms:source element.
>
>         Example, instead of ...
>
>         <rdf:Description rdf:about="http://schema.org/Person">
>         <rdf:type
>         rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"/>
>         <rdfs:label xml:lang="en">Person</rdfs:label>
>         <rdfs:comment xml:lang="en">A person (alive, dead, undead, or
>         fictional).</rdfs:comment>
>         <rdfs:subClassOf rdf:resource="http://schema.org/Thing"/>
>         <rdfs:isDefinedBy rdf:resource="http://schema.org/Person"/>
>         </rdf:Description>
>
>         where I see a clear abuse of rdfs:isDefinedBy, since if you
>         dereference the said URI, you don't find any explicit RDF
>         definition ...
>
>         I would rather have the following
>
>         <rdf:Description rdf:about="http://schema.rdfs.org/Person">
>         <rdf:type
>         rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"/>
>         <rdfs:label xml:lang="en">Person</rdfs:label>
>         <rdfs:comment xml:lang="en">A person (alive, dead, undead, or
>         fictional).</rdfs:comment>
>         <rdfs:subClassOf rdf:resource="http://schema.rdfs.org/Thing"/>
>         <dcterms:source rdf:resource="http://schema.org/Person"/>
>         </rdf:Description>
>
>         To the latter declaration, one could safely add statements like
>
>         schema.rdfs:Person rdfs:subClassOf  foaf:Person
>
>         etc
>
>         Or do I miss the point?
>
>         Bernard
>
>         2011/6/3 Michael Hausenblas <michael.hausenblas@deri.org
>         <mailto:michael.hausenblas@deri.org>>
>
>         http://schema.rdfs.org
>
>         ... is now available - we're sorry for the delay ;)
>
>         Cheers,
>               Michael
>         --
>         Dr. Michael Hausenblas, Research Fellow
>         LiDRC - Linked Data Research Centre
>         DERI - Digital Enterprise Research Institute
>         NUIG - National University of Ireland, Galway
>         Ireland, Europe
>         Tel. +353 91 495730
>         http://linkeddata.deri.ie/
>         http://sw-app.org/about.html
>
>
>
>
>
>         -- 
>         Bernard Vatant
>         Senior Consultant
>         Vocabulary & Data Integration
>         Tel:       +33 (0) 971 488 459
>         Mail:     bernard.vatant@mondeca.com
>         <mailto:bernard.vatant@mondeca.com>
>         ----------------------------------------------------
>         Mondeca
>         3, cité Nollez 75018 Paris France
>         Web:    http://www.mondeca.com
>         Blog:    http://mondeca.wordpress.com
>         ----------------------------------------------------
>
>
>
>
>
> -- 
> Bernard Vatant
> Senior Consultant
> Vocabulary & Data Integration
> Tel:       +33 (0) 971 488 459
> Mail:     bernard.vatant@mondeca.com <mailto:bernard.vatant@mondeca.com>
> ----------------------------------------------------
> Mondeca
> 3, cité Nollez 75018 Paris France
> Web:    http://www.mondeca.com
> Blog:    http://mondeca.wordpress.com
> ----------------------------------------------------

-- 
Christopher Gutteridge -- http://id.ecs.soton.ac.uk/person/1248

You should read the ECS Web Team blog: http://blogs.ecs.soton.ac.uk/webteam/
Received on Tuesday, 7 June 2011 09:23:21 UTC

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