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Re: RDF* semantics

From: Martynas Jusevičius <martynas@atomgraph.com>
Date: Sat, 17 Aug 2019 18:19:23 +0200
Message-ID: <CAE35Vmy5d--hnkRqbyyf9OH3M5TvhHVx7wQuxsdFw29WPd0wDg@mail.gmail.com>
To: Kingsley Idehen <kidehen@openlinksw.com>
Cc: Olaf Hartig <olaf.hartig@liu.se>, "public-rdf-star@w3.org" <public-rdf-star@w3.org>
Kingsley,

don't you mean

[ a foaf:Person; foaf:name "Alice"] :claims { [a foaf:Person;
foaf:name "Bob"; foaf:age "23"^^xsd:integer] . } .

Note the graph designation.

On Wed, Aug 14, 2019 at 5:02 PM Kingsley Idehen <kidehen@openlinksw.com> wrote:
>
> On 8/8/19 6:13 AM, Olaf Hartig wrote:
> > On Wed, 2019-08-07 at 12:04 -0400, Kingsley Idehen wrote:
> >> [...]
> >>>> But that's just another RDF sentence/statement constructed from blank
> >>>> nodes (indefinite pronouns):
> >>>>
> >>>> @prefix : <#> .
> >>>>
> >>>> [ a foaf:Person; foaf:name "Alice"] :claims [a foaf:Person; foaf:name
> >>>> "Bob"; foaf:age "23"^^xsd:integer] .
> >>>>
> >> [...]
> >>
> >> It states that a Person named "Alice" :claims a Person named "Bob" has
> >> age 23 expressed as in integer.
> > I disagree. It states that a Person named "Alice" :claims something and
> > this something is of rdf:type foaf:Person. So, what she is claiming is a
> > person rather than being about a person.
>
>
> I hope you are not interpreting :clams somewhat whimsically, since I
> didn't actually assert that the rdfs:range of :claims is an
> rdf:Statement instance in my original example sentence. I could have
> written my example as follows, to be more precise:
>
> @prefix : <#> .
>
> :claims a rdf:Property ;
>         rdfs:range owl:Thing .
>
> [ a foaf:Person; foaf:name "Alice"] :claims [a foaf:Person; foaf:name
> "Bob"; foaf:age "23"^^xsd:integer] .
>
>
> If on the other hand I had stated:
>
> @prefix : <#> .
>
> :claims a rdf:Property ;
>         rdfs:range owl:Thing .
>
> [ a foaf:Person; foaf:name "Alice"] :claims [a foaf:Person; foaf:name
> "Bob"; foaf:age "23"^^xsd:integer] .
>
>
> Then I would be articulating what you assumed, and my sentence would then be incorrect :)
>
> BTW -- I can also do all of this in a document (as per SPARQL Named
> Graphs) and just pepper the document with additional metadata for
> provenance purposes. Basically, why aren't  SPARQL Named Graphs a viable
> solution to this problem i.e., RDF stays as is for data definition while
> languages such as SPARQL handle operations on RDF structured data?
>
>
> >
> >> [...]
> >>> I guess what you actually wanted to write was something
> >>> like the following:
> >>>
> >>> [ a foaf:Person; foaf:name "Alice"]
> >>>            :claims [ a rdf:Statement ;
> >>>                      rdf:subject   :Bob ;
> >>>                      rdf:predicate foaf:age ;
> >>>                      rdf:object    "23"^^xsd:integer ] .
> >>
> >> No, that is just a reified version of my initial statement.
> > Are you saying that you consider the set of triples serialized as this
> > piece of Turtle to be semantically equivalent to the set of triples
> > serialized in the piece of Turtle above?
>
>
> Of course not.
>
>
> Kingsley
>
> >
> >> [...]
> >>> By the definition of the RDF* data model, every RDF graph is an RDF*
> >>> graph. Additionally, by the definition of the RDF*-to-RDF mapping, every
> >>> RDF* graph can be viewed as an RDF graph.
> >> Sorta, but this is serious work to be done explaining all of this in a
> >> manner that prevents the confusion I fear.
> > Point taken.
> >
> > Olaf
> >
> >
> >
>
> --
> Regards,
>
> Kingsley Idehen
> Founder & CEO
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>
>
Received on Saturday, 17 August 2019 16:19:58 UTC

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