Re: voting against use of rdf:ReificationProperty

On Sep 2, 2024, at 5:25 AM, William Van Woensel <william.vanwoensel@gmail.com> wrote:
> 
>> 
>> OK,I guess that I now see where do you come from.
>> So, If I understand well, your issue is somehow about backward compatibility.
>> Namely: what happens to graphs using perfectly valid “old-style” reification together with RDF-star style reification (according to <https://github.com/w3c/rdf-star-wg/wiki/RDF-star-%22alternative-baseline%22>)?
>> In the example above, there will be the entailments:
>> rdf:object a rdf:reificationProperty.
>> <y> a rdf:reificationProperty.
> 
>  Ah yes, I had not understood the synthesis of the problem either. Thanks for clarifying.
> 
>>> I don’t think there is any "mistake in their model” here, which suggests to me that at least in some cases it is reasonable to have a property whose range includes both triple terms *and* non-triple terms. I’m interested here less in whether “both cases are fine,” and more in whether “both cases AT THE SAME TIME are fine” (and therefore whether it’s even right to talk about “WHICH one makes sense in their context”).
>> 
>> Note that the above happens only when you MIX old style reification with RDF-star style reification in the same graph.
>> That is, you use old style reification (with rdf:object) for a triple which contains a triple term (which cannot happen in RDF-1.1).
>> Clearly, you get bizzarre consequences, IMHO.
>> So, we need to state in the documentation of RDF-star that it is not advisable to use old style reification together with RDF-star style reification in the same graph - a perfectly reasonable request, I guess.
> 
> My two cents remain the same here. They will see "rdf:object" appearing as a ReificationProperty - a feature of RDF 1.2 - and _:a and _:b may be flagged as rdf:Statements - a feature of RDF 1.0-1, if those semantics are also implemented. Under RDF 1.2 semantics, inferring rdf:object as a reificationProperty simply explicates the implications of what is being said: in this case, rdf:object being used as a reificationProperty. The fact that the author is relying on old-style reification is not relevant IMO. Apologies if I'm still misunderstanding.
> 
> This may be a problem for them, or not. I agree that there is no mistake in their model, since there is no particular inconsistency (in contrast to e.g., OWL cardinality constraints being violated). Personally, I would likely not choose to model things that way, and it is certainly against the intended usage. 

Can you expand a bit on "it is certainly against the intended usage”? What is the intended usage you’re referring to, and in what way is my example against it?

thanks,
.greg