Re: Possibility of an LPG-profile

Not to spoil this discussion, but I’m still not sure if a profile is needed in the first place - as asked about in [0].

Best,
Thomas

[0] https://lists.w3.org/Archives/Public/public-rdf-star-wg/2024Aug/0043.html


> On 21. Aug 2024, at 18:02, Lassila, Ora <ora@amazon.com> wrote:
> 
> I have been thinking a lot what I would like to see in an “LPG-profile”. Here are my current thoughts:
>  
> The general question, of course, is this: “Are profiles harmful for RDF-star, and if they are, why?” In other words, if we define profiles, what will blow up downstream?
>  
> A minimal “LPG-profile” (for the lack of better name) would be a restriction on the current baseline model of RDF-star that would make the rdf:reifies -property (or whatever name we ultimately choose for it) functional. In other words, it would ensure that a reifier (identifier) only reifies a single triple. This allows us to treat reifiers as LPG edges, and statements about reifiers (i.e., statements about “triple occurrences”) would then correspond to LPG edge properties. RDF is more expressive, though, allowing the objects of these statements to be nodes in the RDF graph, not just literals like in LPGs. This would be fine.
>  
> My questions about any of this are at least the following:
> 1 – Is this a syntactic or a semantic restriction?
> 2 – If we do this, or some other profile-based restriction, what are the consequences for semantics (as defined in the baseline)?
> 3 – Is it still possible to define entailment regimes (beyond simple entailment) on top of this (RDFS & OWL, namely)? That is, can the restriction be violated by way of entailments?
> 4 – From the implementation standpoint, are there aspects of RDF-star we have not yet considered? For example, does allowing IRIs as reifiers present a burden for implementers (say, considering scenarios where a triple store learns after the fact that the subject of some statements is indeed a reifier)? Discussing implementation details of upcoming commercial products is not easy, of course. Since an LPG-profile would be (potentially) interesting to people also implementing LPG support, their implementation choices may not be the same as those just implementing RDF. Your mileage may vary.
>  
> Sorry I did not get this email out earlier. I am hoping we can discuss the general idea and possibility of profiles tomorrow.
>  
> Ora
>  
> -- 
> Dr. Ora Lassila
> Principal Technologist, Amazon Neptune