Re: RDF-star Agenda for 2021-09-17

On 16/09/2021 19:07, Fabio Vitali wrote:
> Dear all,
>
> My main reason of interest in RDF* is the mechanism to express a triple without stating it (quoted triples, formerly embedded triples). I think that that postulating (i.e., expressing without asserting) is an extremely worthy thing to have and work with. I think that it is truly a fundamental and innovative aspect of RDF*.
>
> Still, I am concerned that this applies only to individual triples and that annotations are considered just a syntactic trick to represent at the same time both a quoted triple and its assertion.
>
> I am wondering, specifically, if the fact that quoted triples are postulated but not asserted came out as a pleasant side effect of the peculiar type of reification adopted for the formal model of RDF* triples, or if this feature was (is, will be) considered as a true design goal for the group, and if there are plan to explore this specific subtree of additional features.
This is not a mere side effect, but the outcome of long discussions 
which we tried to summarized in an appendix the spec [1].
>   
>
> If this is the case, then I am wondering if there is an interest in discussing sooner or later about the following:
>
> 1) promote annotations to first class citizens of the model, and not just leaving them as syntactic shortcuts

this seems to relate to something else you wrote in your previous 
e-mail: "annotations are shorthands for two separate triples".

First, let me point out a difference in terminology which might foster 
misunderstanding in this discussion. IIUC, what you call an annotation 
is statement about a conjecture. In RDF-star, an annotation is a 
statement about an /asserted/ triple (a "collapsed conjecture" in your 
terminology, I believe -- leaving aside the fact that your conjectures 
can have multiple triples).

So in RDF-star:

   << :hamlet dc:creator :shakespeare >> :statedBy :johnson.

is /not/ called an annotation.  It is simply a nested triple (i.e. a 
triple containing another triple). And to answer your point above: this 
thing /is/ a first class citizen in RDF-star.

Second, if I was now to assert the fact that Shakespeare wrote Hamlet, I 
would now have two triples:

   :hamlet dc:creator :shakespeare.
   << :hamlet dc:creator :shakespeare >> :statedBy :johnson.

and you wrote in your previous e-mail "there is no specific relationship 
between the two triples". I would argue the contrary: it is important to 
remember that the triple ':hamlet dc:creator :shakespeare' is /one and 
the same thing/ everywhere it occurs (either asserted or embedded). So 
the two triples above are as strongly related as, for example, the two 
triples below:

   :hamlet rdf:type :Play.
   :hamlet dc:creator :shakespeare.

> 2) extend the reach from postulated triples to postulated graphs

If we did this, RDF-star would have little benefit compared to 
named-graphs (which are already part of RDF). Actually, some people have 
argued that RDF-star is not required, as it can be "emulated" using 
named graphs.

Another way to answer this is (as Andy already did [2]) is that you can 
use RDF-star as a building block to address this use-case:

[ a :Conjecture
   :contains
     << :hamlet dc:creator :shakespeare >>,
     << :hamlet dc:created "1603"^^xsd:gYear >>
] :source <https://en.wikipedia.org/wiki/Hamlet>.

> 3) include mechanisms to postulate the postulation of triples/graphs (already doable)
> 4) include mechanisms to postulate the assertion of postulated triples/graphs
> 5) work with the cascade effect of asserting chained postulations
I have to think more about what the last two points would mean for 
RDF-star, but my gut feeling is that this could be built on top of it 
using a dedicated vocabulary (with a specified semantics).
> If there is an interest in some of these topics, I would very much like to take part and contribute actively to the discussions, and I would like to know how and where and when should the discussion items be introduced.

Well, the mailing list is a good start :)

We also use issues on the github repo [3], and finally, as stated in the 
end of the agenda, anyone is free to propose new topics to be added as 
an agenda item.

   best

[1] 
https://w3c.github.io/rdf-star/cg-spec/2021-07-01.html#sa-mode-and-pg-mode
[2] https://www.w3.org/mid/747a7ef7-da94-ae94-8532-46c29ed95e77@apache.org
[3] https://github.com/w3c/rdf-star/issues
> Thank you
>
> Fabio Vitali
>
> --
>
>> On 16 Sep 2021, at 17:50, Pierre-Antoine Champin <pierre-antoine.champin@ercim.eu> wrote:
>>
>> Hi all,
>>
>> Here are the information for our next call:
>>
>> Meeting: RDF-star
>> Chair: pchampin
>> Time: 3pm UTC https://www.timeanddate.com/worldclock/fixedtime.html?msg=RDF%2A+call&iso=20210917T15&p1=1440&ah=1
>> Place: -
>> Audio: https://mit.zoom.us/j/96863217029?pwd=eHNlS3VBSjVvL0pnV1ptekp6YVZsdz09 (Zoom: 968 6321 7029 - password: rdf-star)
>> IRC: #rdf-star on public-irc.w3.org port 6697 (irc://public-irc.w3.org:6697/%23rdf-star or https://irc.w3.org/)
>> Previous meeting: https://w3c.github.io/rdf-star/Minutes/2021-09-04.html
>> Next meeting: https://w3c.github.io/rdf-star/Minutes/2021-10-01.html
>>
>>
>> 1. Announcements and newcomers
>> ------------------------------
>>
>>
>> 2. Open actions
>> ---------------
>>
>> https://github.com/w3c/rdf-star/issues?q=is%3Aopen+is%3Aissue+label%3Aaction
>>
>>
>> 3. PR #204: Classes for RDF-star terminology
>> --------------------------------------------
>>
>> https://github.com/w3c/rdf-star/pull/204
>>
>>
>> 4. Defining our path
>> --------------------
>>
>> https://lists.w3.org/Archives/Public/public-rdf-star/2021Sep/0001.html
>>
>>
>> 5. Open-ended discussions
>> -------------------------
>>
>>
>> As usual, feel free to make proposals if you would like to add items to this Agenda.
>>
>> best
>> <OpenPGP_0x9D1EDAEEEF98D438.asc>