Re: Two profiles: technical definition

On 2 May 2024, at 12:41, Olaf Hartig <olaf.hartig@liu.se> wrote:

> 1/ Your grammar for the abstract syntax in both of the profiles
> contains the restriction that triple terms cannot be nested. For
> instance, the following 3-tuple (having another 3-tuple as its third
> element which, in turn, has yet another 3-tuple as its third element)
> would not be an RDF triple that one may have in an RDF graph.
> 
> (:r1, rdf:reifies, (:r2, rdf:reifies, (:s,:p,:o) ) )
> 
> I am not against this restriction. I just want to call it out
> explicitly.

I noticed that myself this morning. I would be in favour of arbitrarily nested triple terms, since (a) they make sense, (b) they are well defined in the semantics, and (c) they wouldn’t add any serious additional complexity in the algorithms (it is still pure matching, albeit in a structure with no predefined depth).

> 2/ The definition of the notion of a 'model' in the "functional opaque"
> profile contains an additional formula within which it says
> IEXT(IS(rdf:edge)). This assumes that IS(rdf:edge) ∈ IP. Would it be
> useful to make this assumption explicit in point 3 of the definition of
> the notion of an 'RDF simple interpretation'?

It would be redundant, since that condition plays a role only when rdf:edge is actually used as a property in the graph, in which case IS(rdf:edge) ∈ IP has to hold.

> 3/ Based on the definition of the "functional opaque" profile, it is
> still possible to have two different triple terms t1 and t2 (i.e., t1
> != t2) that an RDF simple interpretation maps to the same resource,
> IL(SRE(t1) = IL(SRE(t2). Is that intentional?
> 
> (I understand that the literals l1 = SRE(t1) and l2 = SRE(t2) are
> different---because SRE is bijective---but IL is not bijective, and
> shouldn't be.)

I assume that this could be fixed by saying that this literal belongs to a special ad-hoc datatype, where the interpretations of different literals would be different.

cheers
—e.


> On Thu, 2024-05-02 at 07:05 +0000, Franconi Enrico wrote:
>> 
>> (I repeat a previous email, which could have been lost within a
>> previous thread)
>> 
>> In order to make the upcoming discussion more concrete and technical,
>> I have written down the formal definition of two profiles in the
>> wiki:
>> RDF-star profile “transparent” (namely many-to-many transparent)
>> RDF-star profile "functional opaque” (namely many-to-one opaque)
>> They rely on two distinct properties - rdf:reifies and rdf:edge
>> (temporary name) - and on two distinct syntactic categories -
>> tripleTerm and opaqueTripleTerm.
>> Technically, they could be just merged into a unique profile, which
>> actually could be RDF-star itself.
>> 
>> —e.

Received on Thursday, 2 May 2024 11:32:47 UTC