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

On 2/16/24 12:17, Pierre-Antoine Champin 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.

Please don't - this just makes things much harder to read.

> (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")
>    )
> )

This is, as far as I can tell.

<< e | s p o >> a b.
e c 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")
>    )
> )

This is, again as far as I can tell.

e a b.
<<e | s p o>> c 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))
>    )
> )

And again

e a b .
e c d .
e rdf:nameOf << s p 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

I think what you are trying to say is that if tripleOccurence is part of RDF 
graphs then pattern matching has to be extended.  Well, yes, just like if 
tripleTerm is part of RDF graphs pattern matching has to be extended as well. 
It is just that the extension for the latter is simple.  To match tripleTerm, 
just match the components.  The situation for tripleOccurence is a bit more 
complex - if there is something like rdf:nameOf then there is a post-graph 
expansion and then regular pattern matching; if there isn't then part of 
pattern matching is to construct a side partial mapping from IRIs to triple 
terms use that mapping to expand matching for IRIs.  But the point is that no 
matter what additions are made to RDF graphs pattern matching has to be expanded.

peter

Received on Friday, 16 February 2024 18:26:43 UTC