Re: RDF-star semantics: option 3 (first DRAFT)

I am advocating (in my last email) just the opposite approach:

- disallow triple terms, e.g.:

    (triple-term (iri "ex:s") (iri "ex:p") (iri "ex:o))

- and disallow rdf:nameOf triples, e.g.:

    (triple

       (iri "ex:e")

       (iri "rdf:nameOf")

       (triple-term (iri "ex:s") (iri "ex:p") (iri "ex:o))
  )

- keep only triple occurrences terms, e.g.:

    (triple
       (triple-occurence (iri "ex:e") (iri "ex:s") (iri "ex:p") (iri "ex:o))
       (iri "ex:a”)
       (iri "ex:b”)
      )

Just like in CG, there is simple encoding (in the shape of option 2) in which simple entailment based on matching works.
—e.


On 16 Feb 2024, at 18:17, Pierre-Antoine Champin <pierre-antoine@w3.org> wrote:


Thanks Enrico for this proposal.

I strongly suggest that we get rid of the orange part, with an argument similiar to what Andy brought up during the Semantics TF call today -- and pushing Andy's argument forward.

The orange part make "triple occurrences"  part of the abstract syntax. Regardless of the name, I think it is a bad idea.

In the following, I'll use a lisp-like representation of the abstract syntax, hopefully self-explanatory.

(graph
  (triple
    (triple-occurence (iri "ex:e") (iri "ex:s") (iri "ex:p") (iri "ex:o))
    (iri "ex:a")
    (iri "ex:b")
  )
  (triple
    (iri "ex:e")
    (iri "ex:c")
    (iri "ex:d")
  )
)

According to your semantics, it would be semantically equivalent to the following graph

(graph
  (triple
    (iri "ex:e")
    (iri "ex:a")
    (iri "ex:b")
  )
  (triple
    (triple-occurence (iri "ex:e") (iri "ex:s") (iri "ex:p") (iri "ex:o))
    (iri "ex:c")
    (iri "ex:d")
  )
)

which would also be equivalent to

(graph
  (triple
    (iri "ex:e")
    (iri "ex:a")
    (iri "ex:b")
  )
  (triple
    (iri "ex:e")
    (iri "ex:c")
    (iri "ex:d")
  )
  (triple
    (iri "ex:e")
    (iri "rdf:nameOf")
    (triple-term (iri "ex:e") (iri "ex:s") (iri "ex:p") (iri "ex:o))
  )
)

We are talking about simple entailment here, not some sophisticated semantic extension.
This breaks a very important feature of the simple entailment in RDF 1.1, namely: it can be computed by doing simple pattern matching of graphs: https://www.w3.org/TR/rdf11-semantics/#dfn-interpolation


Clearly, there is no simple pattern matching method that can detect that the 3 graphs above entail each other.

  pa

On 16/02/2024 15:58, Franconi Enrico wrote:
<https://github.com/w3c/rdf-star-wg/wiki/RDF%E2%80%90star-semantics:-option-3>
RDF‐star semantics: option 3<https://github.com/w3c/rdf-star-wg/wiki/RDF%E2%80%90star-semantics:-option-3>
github.com<https://github.com/w3c/rdf-star-wg/wiki/RDF%E2%80%90star-semantics:-option-3>
<apple-touch-icon-180x180-a80b8e11abe2.png><https://github.com/w3c/rdf-star-wg/wiki/RDF%E2%80%90star-semantics:-option-3>

<OpenPGP_0x9D1EDAEEEF98D438.asc>