Re: owl:sameAs/referential opacity Re: Can RDFstar be defined as only syntactic sugar on top of RDF (Re: weakness of embedded triples)

On 29/10/2020 01:14, thomas lörtsch wrote:

> Pierre-Antoine,
>
> I sympathize with the goal of referential opacity but it seems like you have to work hard against the mechanics of RDF to achieve something within RDF that RDF by its very nature does not only not support but rather aims to get past.
I wouldn't go as far as stating that RDF aims to get past referential
opacity. For example, Notation 3 has managed since the early days to
extends RDF with a referential opacity. But that's another topic :)
> Another question is if the need for referential opacity isn’t rather special and therefor could better be realized through a special mechanism rather than as the guiding design principle. Provenance is only one use case for statement annotation and even then the demands are usually not as extreme as your semantics try to support.

Granted. I created a strawpoll to evaluate how much this feature is
required.

https://github.com/w3c/rdf-star/issues/22

> The argument that it’s easier to add functionality than to take it away later sounds good and true but maybe it’s not when the system within which you are working - RDF - is already based on another paradigm.
>
> Why not go another route and document the original statement as a string
Because asking something like "Does Alice says anything about Paris's
population" would become cumbersome. But apart from that, of course,
this is a way to do it in standard RDF.
>  - withdrawn from all greedy reasoners - when the need arises and in all other cases just live with the unavoidable unhelpful entailment now and then. That’s actually not my idea but yours, below ;-)
>> On 28. Oct 2020, at 19:31, Pierre-Antoine Champin <pierre-antoine.champin@ercim.eu> wrote:
>>
>> (...)
>>
>> RDF(S) semantics makes no distinction between "stated triples" and "inferred triples". So unless we change the semantics of RDF (!),
> !!

Yes, I wrote that, and you seem to imply that I am contradicting myself,
but I don't think I am ;-)

RDF(S) semantics knows nothing about "embedded triples", which are
neither "stated" (I should probably have written "asserted") nor
"inferred". So it is up to us to decide how this new kind of triples
should be handled. This is what this whole discussion is about.