Re: An update on [Proposal: described vs stated triple terms]

On 08/08/2024 12:59, Thomas Lörtsch wrote:
> 
> 
> Am 8. August 2024 13:37:26 MESZ schrieb "Thomas Lörtsch" <tl@rat.io>:
>>
>>
>>> On 6. Aug 2024, at 16:16, Andy Seaborne <andy@apache.org> wrote:
>>>
>>>
>>>
>>> On 05/08/2024 16:37, Thomas Lörtsch wrote:
...

>>>> some help from SPARQL.
>>>
>>> If it is RDFS-star entailment regime, there is nothing extra to do in SPARQL.
>>
>> Yes, if … but in general we can’t rely on RDFS entailment to be available to us.

Then we agree then that it needs to work for simple entailment?

...
>>>  From a data access point of view, multiple properties are a burden in query writing, it would be better to qualify the reifier:
>>>
>>> Data:
>>>
>>>    :r rdf:reifies <<( :s :p :o )>> .
>>>    :r rdf:type rdf:Stated .
>>>
>>> then
>>>
>>>   SELECT ?r {
>>>     ?r rdf:reifies ?T .
>>>   }
>>>
>>> finds all reifiers
>>>
>>>   SELECT ?r {
>>>     ?r rdf:type rdf:Stated .
>>>   }
>>>
>>> finds stated ones
>>> and
>>>
>>>   SELECT ?r {
>>>     ?r rdf:type rdf:Description .
>>>   }
>>>
>>> finds describing reifiers.
>>>
>>> This is open - there can be other characteristics related to reifiers e.g source.
>>
>> We discussed this already: it solves the problem to some degree, but it adds considerably to the triple count. Would you want the canonical mapping from

>>
>>    :s :p :o {| :a :b |} .
>>
>> to n-triples to be
>>
>>    :s :p :o .
>>    _:r rdf:reifies <<( :s :p :o )>> .
>>    _:r rdf:type rdf:Stated .
>       _:r :a :b.
> 
>> ?

No rdf:type.

I don't believe that are only two cases of "stated" and "document". I 
don't believe we can or should enumerate the possibilities - that is the 
responsibility of data modelling.

Most data is "light weight modelling". The most common usage will be 
reification with no opinion as to stated/document.

The RDF way is to add information as needed. No information means "not 
known".

rdf:type might be inferred by the domain of a property in the annotation 
block.

We might even have "rdf:type rdfx:Edge" with special meaning for the LPG 
use case.

>> You were concerend about additional query complexity if a second property like rdf:states as a subproperty of rdf:reifies is introduced. How would the necessity to query for an extra typing triple compare to that?

subproperty is a feature of RDFS.


SELECT ?r {
      ?r rdf:reifies ?T .
   }

and if the query is looking for only stated:

SELECT ?r {
      ?r rdf:reifies ?reif .
      ?reif rdf:type rdf:Stated .
}

which can be

SELECT * {
    ?r rdf:reifies [ rdf:type rdf:Stated ] .
}

SELECT * {
    ?r rdf:reifies/rdf:type rdf:Stated .
}

    Andy

>>
>> Thomas
>>
>>
>>>     Andy
>>>
>>
>> [0] https://lists.w3.org/Archives/Public/public-rdf-star-wg/2024Aug/0032.html
>> [1] https://w3c.github.io/rdf-star/cg-spec/2021-12-17.html#example-14
>>
>>>
>>
>>

Received on Thursday, 8 August 2024 13:14:18 UTC