Re: Presentation about reifiers and graphs

On 20 Sep 2024, at 06:57, Niklas Lindström <lindstream@gmail.com> wrote:
Slide 3
(akin to literals) ==> dangerous parallel, I’d delete it.

Why is it dangerous? I know you've had reservations about literals
denoting resources; but as they are defined (as a tuple of a lexical
string and an IRI, and as denoting a value in the value space of the
datatype this IRI denotes), I do think there is a structural parallel
(as opposed to the primitive(?) IRIs and bnodes). But perhaps that is
too superficial a parallel.

Because the parallel, if you really want to make one, is with a composite term (as opposed to atomic terms, such us IRIs, bnodes, literals) made up with IRIs, bnodes, literals, and possibly other composite terms.

To me, this goes back to the question about what they denote. (A
constituent of the graph or a propositional atom of the model? I tried
to touch on that only lightly...)

Any term (atomic or composite) denotes a resource, not only literals...

Slide 4
...you need to identify them as concrete... ==> ...you need to associate them to concrete…

How about "To describe such things, you need to refer to triples from
concrete reifying resources."?

Convolute, but better :-)

I don’t really understand why you spend so much time on named graphs. This may lead to endless discussions we are not prepared to handle. I repeat my arguments to avoid discussions:

Well, part of the task as I took it was to present something about the
difference between reifiers and (named) graphs. This has been asked
this many times, and we did touch upon it during the last TPAC, IIRC.

I didn't want to go into the union vs. merge details too much in the
slides, as I thought focusing on refiers being within one graph was
more to the point. But I will make an attempt (if I can find enough
time), certainly considering your wording (and the rest of the thread
on this list) to reduce or otherwise improve the latter part of the
presentation.

Again, the main point being: as such, rdf 1.2 is unable to capture named graphs in their generality, but only named graphs with union semantics.

My conclusion: these things need to be discussed, and we haven’t done it yet, and therefore I’d restrain to say that we can represent named graphs.

I agree that we need to discuss it, and I don't want to present
something contentious as if it was decided.

See above my main point.

A thanks for the effort!
--e.

On 19 Sep 2024, at 06:30, Niklas Lindström <lindstream@gmail.com> wrote:

Dear all,

Thank you all for the valuable feedback! I've read all replies
(including those off-list) and much appreciate the help. (My lack of
replying is due to lack of time.) Alas, I've not yet been able to
collate and address it all (I was away on a conference), but I've
updated the presentation with some few adjustments and additions (it
is still at [1], with diffs at [2]).

The goal is to introduce reifiers, and also to compare them to graphs
and named graphs, since questions about their differences are
recurring. I want this to make sense practically, without straying
from formal definitions. As expected, there are some disputed points;
and I appreciate all help in reaching these goals. I'm sure the
presentation can be made shorter, clearer, and more inclusive.

(If I sense there is enough rough consensus on its message, I'd be
happy to present this at TPAC on behalf of the group.)

Best regards,
Niklas

[1]: <https://niklasl.github.io/rdf-docs/presentations/RDF-reifiers-1/>
[2]: <https://github.com/niklasl/rdf-docs/compare/main...dev>


On Sat, Sep 14, 2024 at 1:28 PM Niklas Lindström <lindstream@gmail.com> wrote:


Dear all,

I've drafted a presentation for the purpose of introducing reifiers
and comparing them to graphs. It's currently at:
https://niklasl.github.io/rdf-docs/presentations/RDF-reifiers-1/


Ora: you're of course free to take what you like and discard the rest
for your TPAC slides.

I tried to keep it on par with the baseline, but of course there may
be wording in there still to be agreed upon. If you see fit I can make
a PR for further collaboration in getting a version of it to
https://github.com/w3c/rdf-star-wg/tree/main/docs.


Best regards,
Niklas