Re: "Multi-Edge Support in RDFn" slides

Thomas,

note that my argument was not so much about paradoxes, than about 
self-referential statements (which can be paradoxical or not, but lead 
to a nasty class of paradoxes).

That being said:

On 13/12/2022 14:25, Thomas Lörtsch wrote:
> How about
>
>      :A a :Lie .
>      << :A a :Lie >> owl:sameAs :Aq .
>      :Aq a :Lie .

This example is not self-referential, but could be made self-referential

   :A a :Lie.
   << :A a :Lie >> owl:sameAs :A.

So I stand corrected: RDF-star is just as exposed to this kind of 
paradox as RDFn.

Note, however, that this is not a paradox until you define the semantics 
of owl:sameAs (which is not part of RDF-star's base semantics) and of 
:Lie. I believe it would be possible to define the semantics of :Lie in 
a way that would not blow up in our face in the case above -- but I 
would have to think about it a bit longer.

> Doesn’t that overcome RDF-star's syntactic safe guard against paradoxes? And if it does - I’m not a logician, so I’m not sure - aren’t the consequences even worse for RDF-star than for RDFn, as the paradox targets all occurrences of type << :A a :Lie >>, not only one instance as in RDFn’s case.

Not, it does not targets all occurrences, because the occurrences are 
/distinct/ from the type -- or, as you phrase it in terms of the 
type-token distinction: the tokens are distinct from the types. That's 
why it's called type-token /distinction/. :-)

   pa
>
> I haven’t fully understood how the RDF 1.x semantics tackles this topic [0] but as I said before my intuition is that going the way of occurrences (which in my understanding is a more generic term for both instances and subtypes, which - see OWL punning - are rather application specific categories) opens the same venue: interpreting a statement as a concrete occurrence of the type instead of as the type itself (as the RDF-star semantics proposes) separates the two, puts the occurrence in the extension of the type, and thereby avoids paradoxes in the semantics already.
>
> Thomas
>
>
> [0]https://www.w3.org/TR/rdf-mt/#technote

>
>
>> On 9. Dec 2022, at 08:15, Pierre-Antoine Champin<pierre-antoine@w3.org>  wrote:
>>
>> Thanks Souri,
>>
>> I added a link to the slides in the minutes of the call where you presented them.
>> https://www.w3.org/2022/11/17-rdf-star-minutes.html

>>
>> A few remarks about slides 8 and 9:
>> - what you call semantics in these slides is more related to the RDF abtract syntax [1] than the RDF semantics [2]. The former is about structural elements of RDF (IRIs, triples...) while the second is about the "things in the world" that the RDF graph is about.
>>
>> - In those slides, I see no constraint about preventing triples to talk about themselves (which the CG report explicitly forbids [3]). This allows for something like
>>
>>    :t1 a :Lie (:t1).
>>
>> or, even more tricky to detect
>>
>>    :t2 a :Truth (:t1).
>>    :t1 a :Lie (:t2).
>>
>> This kind of paradoxes may be tricky to model in terms of semantics....
>>
>>    pa
>>
>> [1]https://www.w3.org/TR/rdf11-concepts/

>> [2]https://www.w3.org/TR/rdf11-mt/

>> [3]https://www.w3.org/2021/12/rdf-star.html#concepts   "Note also that, by definition, an RDF-star triple cannot contain itself"
>>
>> On 03/12/2022 00:21, Souripriya Das wrote:
>>> Attached a revised version of the RDFn slide deck [1] that includes
>>>  • (slide 8) new slide titled "RDFn Semantics: Essentials, in a few words"
>>>  • (slide 9) corrected slide titled "RDFn Semantics: Essentials Beyond RDF" that now states that TI INTERSECT TE need not be an empty set and shows the corrected diagram
>>>  • (slide 14) new slide titled "Enabling Explicit Naming in RDF-star, Serializations, and SPARQL-star"
>>> Thanks,
>>> Souri.
>>>
>>> [1]https://lists.w3.org/Archives/Public/public-rdf-star-wg/2022Nov/att-0016/RDFn_WG_Slides.pdf

>> <OpenPGP_0x9D1EDAEEEF98D438.asc>
>