Re: Decision from the Semantics TF: liberal baseline

> On 2. Jan 2025, at 17:29, Franconi Enrico <franconi@inf.unibz.it> wrote:
> 
> At the last Semantics TF we discussed about the RDF semantics of the liberal baseline. 
> In the current version of the document:
> https://github.com/w3c/rdf-star-wg/wiki/RDF-star-%22liberal-baseline%22#rdf-semantics
> the two discussed restrictions


Shouldn’t we rather stop calling them restrictions? They define things, but they can’t enforce anything.

> of RDF semantics are formalised:
>     • triple terms, appearing in triples or in triple terms, are of type rdf:proposition;

That seems redundant: triple terms are always of type proposition, they can’t be anything else, or can they? I.e. they _are_ propositions. To me it seems like it would be enough for them to get their own class, in analogy to rdfs:Literals.

I remember the consensus in the SemTF discussion leaning towards the rdf: namespace, but when I look at <https://www.w3.org/TR/2014/REC-rdf-schema-20140225/#ch_classes> I find the rdfs: namespace more fitting, putting rdfs:Proposition right besides rdfs:Resource, rdfs:Class and rdfs:Literal.

>     • objects of the property rdf:reifies, appearing in triples or in triple terms, are of type rdf:proposition.


Mildly in favor of it, as an expression of intent. The property rdf:reifies has a very specific purpose, and expressing that axiomatically might help prevent misuse.

However, looking at the RDFS entailment patterns in <https://www.w3.org/TR/rdf11-mt/#patterns-of-rdfs-entailment-informative>, 
some of them seem rather verbose, like

rdfs4a 
xxx aaa yyy . 
->
xxx rdf:type rdfs:Resource .

some seem useful, like 

rdfs11 
xxx rdfs:subClassOf yyy .
yyy rdfs:subClassOf zzz . 
->
xxx rdfs:subClassOf zzz .

But they all seem evidently valid. The proposed reif axioms however aren’t, they can easily be broken. That rather speaks against them.

> We may decide to have both restrictions, any of them, or none.
> Let’s open the general discussion :-)

Glad to see that you still seem to enjoy it :-)

.t


> —e.
> 
>> On 13 Dec 2024, at 18:20, Franconi Enrico <franconi@inf.unibz.it> wrote:
>> 
>> Today the Semantics TF met, and we agree to submit to the working group a proposal for a liberal baseline. It is summarised in <https://github.com/w3c/rdf-star-wg/wiki/RDF-star-%22liberal-baseline%22>, to be discussed (and voted?) at the first focussed meeting in 2025.
>> Basically, there will be a no syntactic restriction in using both rdf:reifies and triple terms. 
>> Reification is sanctioned only if it makes use of the property rdf:reifies or any of its subproperties; the subject of rdf:reifies is called a reifier.
>> Triple terms would be always of type rdf:Proposition, and the range of rdf:reifies would be rdf:Proposition.

Received on Monday, 6 January 2025 23:06:20 UTC