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

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)

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/

Received on Wednesday, 12 April 2023 11:37:51 UTC