Re: Why nested triples?

The N3 semantics are still being defined, but I already advocated that N3
should be a superset of whatever RDFstar turns out to be:
https://github.com/w3c/N3/issues/27 Anything else would limit its practical
use IMO

On Thu, 18 Feb 2021, 20:30 thomas lörtsch, <tl@rat.io> wrote:

>
>
> > On 18. Feb 2021, at 15:56, Olaf Hartig <olaf.hartig@liu.se> wrote:
> >
> > Hi Antoine,
> >
> > On torsdag 18 februari 2021 kl. 15:02:11 CET Antoine Zimmermann wrote:
> >> The RDF-star syntax allows for arbitrary nesting of triples like so:
> >>
> >> << :s :p << << :a :b :c >> :y :z >> a :nesting .
> >>
> >> Why is it so, why is it useful/needed?
> >> There are no examples of nested triples. There are no justifications in
> >> the spec for allowing this. As far as I know, there are no examples in
> >> the past documents that defined RDF*. I did not see any use cases
> >> discussed for them.
> >
> > How's about something like the following?
> >
> > :charlie :claims << :alice :claims <<:bob :age 23>> >> .
> >
> >
> >> However, I have seen discussions that may serve as counter arguments:
> >> when asked why embedded triples are limited to single triples rather
> >> than sets of triples, it has been answered that RDF* is used to model
> >> property-graph-like annotations that only concern one edge at a time. In
> >> this case, nested triples should not be allowed, using the same
> >> arguments (as far as I know, it is not possible to nest edge-annotations
> >> in property graph systems).
> >>
> >> Nesting makes parsers more complicated, makes it more difficult to
> >> define the semantics of the data model as well as of the query language.
> >>
> >> If some use cases justify nested triples, then why not use cases justify
> >> embedded sets of triples?
> >
> > I still think that a statement about a particular triple is something
> else
> > than a statement about a set of triples (a.k.a. an RDF graph) that
> happens to
> > contain a single triple.
> >
> > For use cases in which you want to have sets of triples in the subject
> > position or the object position of another triple, doesn't N3 allow you
> to do
> > this?
>
> Is RDF* just a subset of N3?
>
> Thomas
>
> >> Also, a question to implementers: do you support nested embedded
> triples?
> >
> > I know that Jena supports it.
> >
> > Best,
> > Olaf
> >
> >
>
>
>