Re: the rationale and history of RDF-star semantics

That's what I thought.   Let's please not ignore the pre-CG history of RDF*.


peter


On 1/19/23 12:04, Antoine Zimmermann wrote:
> The technical report published in arXiv about RDF* 
> (https://arxiv.org/abs/1406.3399) in 2014 (revised 2019 then 2021) does say 
> that embedded triples are syntactic sugar for RDF reification (section 3.2), 
> although it does not use the phrase "syntactic sugar".
>
> --AZ
>
> Le 19/01/2023 à 02:32, Peter F. Patel-Schneider a écrit :
>> How far does this history go back?  Wasn't the original semantics for RDF* 
>> a semantics that treats embedded triples as syntactic sugar for RDF 
>> reification?
>>
>>
>> peter
>>
>>
>>
>> On 1/17/23 08:35, Pierre-Antoine Champin wrote:
>>> Dear Enrico, all,
>>>
>>> following the discussion we had during the last call [1], I would like to 
>>> give a more detail overview of our rationale when designing the RDF-star 
>>> semantics in the CG report [2], and defuse a few misunderstandings.
>>>
>>> 1. It was not the intention to make RDF-star a modal logic
>>>
>>> I know that examples such that ":alice :belives << :s :p :o >>." strongly 
>>> point in the direction of modal logic, and that such examples have been 
>>> largely used to "sell" RDF-star. I agree that such examples are 
>>> misleading, and we actually tried to avoid such examples in the CG report.
>>>
>>> The intention was to make RDF-star quoted triples opaque, and providing as 
>>> little inferences as possible -- leaving it open for semantic extensions 
>>> to provide more inferences.
>>>
>>>
>>> 2. Ground quoted triples are similar to literals
>>>
>>> Our initial attempt was to define from scratch a model theoretic semantics 
>>> of RDF-star, where ground quoted triples (i.e. quoted triples containing 
>>> no blank node) were constrained to denoted themselves. In other words, we 
>>> consider that RDF(-star) triples (as defined by the specification) are 
>>> conceptual objects that exist in the world (in the same way that graphs, 
>>> classes and properties exist), and that ground quoted triples did denote 
>>> exactly them.
>>>
>>> In that sense, ground quoted triples are very much like literals (except 
>>> that they are allowed in the subject position).
>>>
>>>
>>> 3. Blank node rain on our parade (as they usually do)
>>>
>>> Of course, things get tricky when we take blank nodes into account.
>>>
>>> Just like the RDF1.1 Semantics, our proposal was built in two steps :
>>> - define the semantics of ground RFD-star graphs (following the rationale 
>>> described above)
>>> - deal with blank node
>>>
>>> The second step was quite complicated, and it raised some questions about 
>>> whether this brand new semantics was sound. An alternative way was 
>>> therefore proposed, to rely on the battle-tested RDF semantics. And that's 
>>> where we are now.
>>>
>>> Honestly, I would rather give another try at /adapting /the current RDF 
>>> semantics to take into account quoted graphs, than keeping the layered 
>>> approach that we currently have.
>>>
>>>   pa
>>>
>>>
>>> [1] https://www.w3.org/2023/01/12-rdf-star-minutes.html#t03
>>> [2] https://www.w3.org/2021/12/rdf-star.html#rdf-star-semantics
>>>
>

Received on Thursday, 19 January 2023 17:10:01 UTC