Re: Possibility of an LPG-profile

On 21 Aug 2024, at 18:02, Lassila, Ora <ora@amazon.com> wrote:

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.

Let me just provide some material for thoughts - just material, no judgements.


  1.  [0] provides a possible “LPG" profile with just a syntactic restriction,
while [1] (which is the second part of [0]) shows the consequences of a possible “LPG” profile with a proper semantic restriction.
  2.  As [1] shows, a consequence of a proper semantic restriction is that simple entailment cannot be based on simple pattern matching, because (in)equalities are thrown in the mix.
  3.  A semantic restriction for the LPG profile will impose changes in entailment regimes, again due to added (in)equalities in the game.

—e.

[0] https://github.com/w3c/rdf-star-wg/wiki/RDF-star-and-LPGs

[1] https://github.com/w3c/rdf-star-wg/wiki/RDF-star-and-LPGs#a-profile-enforcing-functionality-of-rdfreifies