Re: [Sem] Syntax and model-theoretic semantics: a complete proposal

> On Apr 12, 2023, at 4:37 AM, Antoine Zimmermann <antoine.zimmermann@emse.fr> wrote:
> 
> Enrico,
> 
> While reading your documents, I realised that your syntax, as well as my syntax at https://www.emse.fr/~zimmermann/W3C/RDF-star-semantics/, allow the subject to be a literal. However, I think we can ignore this issue for the moment, as it should not have any impact on the semantics.
> 
> 
> Le 12/04/2023 à 10:18, Franconi Enrico a écrit :
>> I extended my original proposal to include a fully opaque case, so that it can represent both the fully opaque case (syntactic predication) and the fully transparent case (semantic and modal predications).
>> Now the proposal comes with a completely specified abstract semantics, etc.
>> This proposal comes in three flavours, depending on the syntax chosen:
>> 1. the Community Group syntax with TEP as it is described in its final
>>    report (wiki: CG syntax specification
>>    <https://github.com/w3c/rdf-star-wg/wiki/Semantics-(CG-syntax)-by-enrico>),
> 
> In section SEMANTICS:
> - "L is a mapping from RTD-star terms or RTD-star triples" -> probably "RDF-star terms or RDF-star triples"
> - The way "RDF-star term" is defined, they include RDF-star triples, so the "or RDF-star triples" is redundent.
> - "in a concrete syntax" -> are there different semantics for different concrete syntaxes?
> - "RDF-star triples in a concrete syntax to their N-triples representation as string" -> N-triples, for the moment, does not have a representation for quoted triples. Also, it has multiple representations for some graphs in a concrete syntaxes, e.g., this Turtle string:
> 
> [] a [] .
> 
> has multiple N-triples representations. You may choose a normalised representation, but then, "[] a []" always denote the same thing everywhere, e.g.:
> 
> <<[] a []>>  :p  <<[] a []>> .
> 
> the subject and object denote the same thing.
> 
> - [I+A] is ill-defined for RDF-star triples. If x = (s,p,o) is an RDF-star triple, it may be the case that [I+A](x) = TRUE or FALSE, or that [I+A](x) = IT([I+A](s),[I+A](p),[I+A](o)). You need a way to distinguish the function that maps terms to resources from the function that maps triples or graphs to {TRUE,FALSE}.
> - I find it strange that the "simple semantics" requires constraints on the interpretation of some specific IRIs (namely rdf:type and rdf-star:TEP)

Note that https://github.com/w3c/rdf-concepts/pull/32 replaces the notion of “RDF-star triple” with “Complex triple”, as discussed in a separate issue [1]. Generally, the terminology is “quoted triple”, “asserted triple”, “complex triple/graph/dataset”, “simple triple/graph/dataset”. This is, of course, subject to discussion and approval, so please weigh in on the PR if you have an opinion.

Gregg

[1] https://github.com/w3c/rdf-star-wg/issues/33

> I do not understand the utility of the examples. They are merely examples of the syntax of Turtle-star.
> 
>> 2. the variant which distinguishes syntactic from semantic quoted
>>    triples (wiki: alt syntax specification
>>    <https://github.com/w3c/rdf-star-wg/wiki/Semantics-(alt-syntax)-by-enrico>),
> 
> Again: "RTD-star" -> RDF-star
> Again, the mapping L is not sufficiently well defined.
> Again, the examples are just showing examples of a concrete syntax.
> 
>> 3. the variant with a quoting operator which gives a syntactic reading
>>    to arbitrary terms (wiki: alt syntax with quoted terms specification
>>    <https://github.com/w3c/rdf-star-wg/wiki/Semantics-(alt-syntax-with-quoted-terms)-by-enrico>).
> 
> The mapping L is only used in the 5th point of [I+A] where r is necessarily a quoted term. L could be defined as a mapping from quoted RDF-star terms to strings. Or, even simpler, L could be eliminated and ITL be defined as a mapping from quoted RDF-star terms to IR. The intermediary mapping to strings does not affect anything.
> 
> 
> --AZ
> 
>> There is a wiki page describing each variant of the proposal.
>> —e.
> 
> -- 
> Antoine Zimmermann
> École des Mines de Saint-Étienne
> 158 cours Fauriel
> CS 62362
> 42023 Saint-Étienne Cedex 2
> France
> Tél:+33(0)4 77 49 97 02
> http://www.emse.fr/~zimmermann/
>