Tentative summary of today's Semantics TF meeting

Hi everyone,

below is my attempt at summarizing the discussion we had today in the 
Semantics TF


presents: Andy, Enrico, Niklas, Peter and myself

We started with a question from Andy:
if :x is an occurrence of (:s :p :o) and :p is a subproperty of :q,
should :x be considered an occurrence of (:s :q :o) ?
-- similar questions could be asked, e.g. with (:s a :C), :C subclass of 
:D and (:s a :D)

The general consensus was that this should not be the case in general,
but some consider that if :x is an occurrence of (:s :p :o) and :o 
owl:sameAs :o2,
then :x should be considered an occurrence of (:s :p :o2).
(referential transparency)

Then we discussed whether triple terms and/or triple occurrences should 
be elements of the abstract syntax.
My reading of Andy's proposal is that only triple terms are part of the 
abstract syntax, occurrences are arbitrary resources.
Andy responded that he had not thought about it so deeply.
Enrico presented his alternative abstract syntax + semantics where 
triple occurrences are part of the abstract syntax, and triple terms are 
absent [1] .

We discussed this for a while, coming to the conclusion that Enrico's 
proposal above and my proposal of an "RDFn" profile of Andy's proposal 
[2] were essentially achieving the same thing, each with its own kind of 
"bizarreness":
* in Enrico's proposal, triple occurrences are bizarre terms, because 
they are acting like a new kind of statement ("naming statement"), and 
they are dependant on other terms (they denote the same thing as their 
first component, the name);
* in PA's proposal, triple terms are bizarre terms because they can only 
be used with one predicate (rdf:occurrenceOf).

Then we discussed about monotonicity and how "temporal annotations" 
(e.g. annotating a triple with start date and end date) could be 
misused. The conclusion was that this was to be addressed by 
schema/ontology designer, by clealy define under which condition the 
temporal annotations should be used. It is not to be addressed at the 
level of RDF itself, which is schema-less.

[1] https://github.com/w3c/rdf-star-wg/wiki/Semantics:-Andy's-proposal
[2] 
https://lists.w3.org/Archives/Public/public-rdf-star-wg/2023Dec/0076.html