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Re: RDF* semantics

From: Martynas Jusevičius <martynas@atomgraph.com>
Date: Sat, 17 Aug 2019 22:18:31 +0200
Message-ID: <CAE35VmzYdB3jwoQH2+jmwo1Y4sjm=7fHh9u_yjfJ3jNqPQiEjA@mail.gmail.com>
To: Kingsley Idehen <kidehen@openlinksw.com>
Cc: public-rdf-star@w3.org
Yes the syntax was more of an "abstract" example.

OK, I guess it makes more sense with rdf:Statement.

I don't have more to add as I haven't really studied the RDF* semantics :)

On Sat, Aug 17, 2019 at 8:45 PM Kingsley Idehen <kidehen@openlinksw.com> wrote:
>
> On 8/17/19 12:19 PM, Martynas Jusevičius wrote:
>
> 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.
>
>
> Not as presented syntactically as that isn't RDF-Turtle notation.
>
> Here's are document URL that includes content representing what Olaf and I are discussing, using RDF-Turtle notation or Nanotation (i.e, "text/plain" file that's readable as is or via our OSDS Browser Extension for visualization):
>
> My original statements in documents without reification :
>
> 1.  https://kingsley.idehen.net/public_home/kidehen/Public/Linked%20Data%20Documents/Tutorials/label-property-graph-stuff/alice-claims-about-bob.txt -- RDF-Turtle Nanotation in plain text (i.e., "text/plain" content-type)
>
> 2. https://kingsley.idehen.net/public_home/kidehen/Public/Linked%20Data%20Documents/Tutorials/label-property-graph-stuff/alice-claims-about-bob.ttl -- RDF-Turtle (i.e., "text/turtle" content-type)
>
>
> Documents comprising reified statements (as per what Olaf is speaking about primarily) using terms from the RDF Vocabulary:
>
> 1. https://kingsley.idehen.net/public_home/kidehen/Public/Linked%20Data%20Documents/Tutorials/label-property-graph-stuff/alice-claims-about-bob-reified.txt -- RDF-Turtle Nanotation in plain text (i.e., "text/plain" content-type)
>
> 2. https://kingsley.idehen.net/public_home/kidehen/Public/Linked%20Data%20Documents/Tutorials/label-property-graph-stuff/alice-claims-about-bob-reified.ttl -- RDF-Turtle Nanotation in plain text (i.e., "text/plain" content-type)
>
>
> As I see it, the issue we are debating is primarily about reification and syntax sugar for articulation convenience i.e., does this actually constitute what's denoted as RDF* Semantics (for which I am currently unconvinced, bearing in mind what exists regarding the roles of RDF [DDL] and SPARQL [DML] which offers Named Graphs as a solution).
>
>
> Kingsley
>
>
>
> 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
> OpenLink Software
> Home Page: http://www.openlinksw.com
> Community Support: https://community.openlinksw.com
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>
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>               http://kidehen.blogspot.com
>
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>
>
>
>
> --
> Regards,
>
> Kingsley Idehen
> Founder & CEO
> OpenLink Software
> Home Page: http://www.openlinksw.com
> Community Support: https://community.openlinksw.com
> Weblogs (Blogs):
> Company Blog: https://medium.com/openlink-software-blog
> Virtuoso Blog: https://medium.com/virtuoso-blog
> Data Access Drivers Blog: https://medium.com/openlink-odbc-jdbc-ado-net-data-access-drivers
>
> Personal Weblogs (Blogs):
> Medium Blog: https://medium.com/@kidehen
> Legacy Blogs: http://www.openlinksw.com/blog/~kidehen/
>               http://kidehen.blogspot.com
>
> Profile Pages:
> Pinterest: https://www.pinterest.com/kidehen/
> Quora: https://www.quora.com/profile/Kingsley-Uyi-Idehen
> Twitter: https://twitter.com/kidehen
> Google+: https://plus.google.com/+KingsleyIdehen/about
> LinkedIn: http://www.linkedin.com/in/kidehen
>
> Web Identities (WebID):
> Personal: http://kingsley.idehen.net/public_home/kidehen/profile.ttl#i
>         : http://id.myopenlink.net/DAV/home/KingsleyUyiIdehen/Public/kingsley.ttl#this
>
Received on Saturday, 17 August 2019 20:19:04 UTC

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