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Re: Annotation syntax [was: SPARQL* test suite]

From: Andy Seaborne <andy@apache.org>
Date: Wed, 2 Sep 2020 11:20:00 +0100
To: public-rdf-star@w3.org
Message-ID: <345f9f3b-a37f-1632-64a6-7f00140a9a55@apache.org>

On 02/09/2020 09:25, Olaf Hartig wrote:
> Hi,
> On onsdag 2 september 2020 kl. 17:44:06 CEST Holger Knublauch wrote:
>> On 2/09/2020 15:41, Patrick J Hayes wrote:
>>> Jeen and Holger, greetings.
>>> It seems to me that there is a more basic issue here. However it is
>>> written, if this maps to an RDF graph containing the triple
>>> :bob :age 23 .
>>> then that triple is /asserted to be true/, and that assertion of truth
>>> is independent of any other triples, be they called ‘annotations’ or
>>> not. Adding a triple to an RDF graph cannot change or modify the
>>> asserted truth of any other triple in the graph, even if it refers to
>>> it. This follows from the monotonicisty of the underlying semantics.
>> [...]
>> It seems that the topic you raise applies to RDF* in general, not just
>> this particular syntax extension here in this thread.
> Right, but only if we make the PG mode assumption for RDF* graphs. In SA mode
> we don't have this issue.

We could view it as no different from nonsensical data modelling.

There is also the annotation with range in wikidata or other pair of 
related statements:


As you can get into the same situation in SA mode, it is there really, 
just not automatically by writing the :certainty triple.


> Olaf
> PS. For everyone who has joined the list recently and wonders what SA mode and
> PG mode are, the following earlier email should give you an answer:
> https://lists.w3.org/Archives/Public/public-rdf-star/2019Sep/0051.html

Good reminder.

For completeness this issue has come up before:

>> Holger
>>> One could of course provide an alternative semantics which would allow
>>> this, but the underlying language would then no longer be RDF.
>>> This of course does not apply to annotations which  record provenance
>>> of triples or describe their status in some way. But an annotation
>>> which changes the truthvalue of a triple is not merely meta-knowledge
>>> or documentation, but rather moves it into a different logic.
>>> Pat Hayes
>>>> On Sep 1, 2020, at 8:07 PM, Jeen Broekstra <jb@metaphacts.com
>>>> <mailto:jb@metaphacts.com>> wrote:
>>>>      Yes, I think so and apologies if I didn't communicate this clearly.
>>>>      The point here is to *add* an alternative short cut so that
>>>>      instead of
>>>>          :bob :age 23 .
>>>>          <<:bob :age 23>> :certainty 0.9 .
>>>>      we can simply (alternatively) write
>>>>         :bob :age 23 {| :certainty 0.9 |} .
>>>>      This would serve as syntactic sugar for the (common) use case of
>>>>      both asserting and annotating a triple, while still allowing
>>>>      free-standing annotations. The short cut will not only make files
>>>>      significantly shorter, but also make editing more user-friendly.
>>>>      The cost is for implementers though, who would have to cover an
>>>>      additional case (both in parser and serializer).
>>>> Thanks for clarifying  - in that case I think it's actually a very
>>>> good idea. The main issue I see with supporting it is in the
>>>> serialization side, which will be tricky to do for any streaming
>>>> writer. However, we could support that kind of thing under the
>>>> moniker of "pretty printing", which is already something that
>>>> requires buffering anyway.
>>>> Jeen
>>>> jb@metaphacts.com <mailto:jb@metaphacts.com>
>>>> www.metaphacts.com <https://www.metaphacts.com/>
>>>> htps://www.metaphacts.com/ <https://www.metaphacts.com/>
Received on Wednesday, 2 September 2020 10:20:16 UTC

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