Re: A proposal for basing quotation and annotation upon blank graphs

On Thu, Oct 5, 2023 at 9:17 PM Andy Seaborne <andy@apache.org> wrote:
>
>
>
> On 05/10/2023 13:02, Niklas Lindström wrote:
> > I have written a follow-up (ttled "Prerequisites and Requirements for
> > Quotation in RDF") to explore some fundamental questions raised by
> > these proposals:
> >
> >      https://gist.github.com/niklasl/c22994e664663b6730613ecc1321c418
> >
> > I look forward to analyzing this further with you.
> >
> > All the best,
> > Niklas
>
> Data:
> _:g1 { :s1 :p1 :o1 }
> _:g2 { :s2 :p2 :o2 }
> _:g1 dc:created "2023-05-20T09:14:30Z"^^xsd:dateTime .
>
> Query: find all the graphs that were created at xsd datetime.
>
> SELECT * {
>   ?x dc:created "2023-05-20T09:14:30Z"^^xsd:dateTime .
> }
>
> Result:
> ?x = _:blank123456789
>
> which isn't very useful to go on and ask questions about the graphs as
> might be done by a UI RDF browser.

That is certainly true. With nothing else that is quite useless. Just
as any bnode id is in a query result (unless persistently skolemized),
such as from a regular reification.

And granted, you'd get the quoted triple "struct" back from your query
with data like:

    << :s1 :p1 :o1 >> dc:created "2023-05-20T09:14:30Z"^^xsd:dateTime .

But even without improved notation for blank graphs, this gives you
that data today (with the arguable "bonus" of potentially multiple
occurrences):

    SELECT * {
        GRAPH ?g { ?s ?p ?o }
        ?g dc:created "2023-05-20T09:14:30Z"^^xsd:dateTime .
    }

There is reasonably little to no value of the blank graph id itself
outside of structure (as with bnodes in general). But as this is about
exploring quotation as structure, I started with the forms we have in
RDF 1.1.

That shows better in the "meatier" examples. The leading parts of my
recent text is only about establishing behaviour. I'm in no way
arguing for the usability of bnode *id:s*, other than perhaps in
corner cases, such as in [1] where the repeated quoted triple could,
with blank node graphs, be further condensed.

/Niklas

[1]: https://github.com/w3c/rdf-ucr/wiki/RDF-star-for-CIDOC-CRM-events

>      Andy
>

Received on Thursday, 5 October 2023 21:13:16 UTC