- From: David Booth <david@dbooth.org>
- Date: Wed, 12 Dec 2018 17:27:38 -0500
- To: Antoine Zimmermann <antoine.zimmermann@emse.fr>
- Cc: Patrick J Hayes <phayes@ihmc.us>, semantic-web@w3.org
On 12/12/18 8:56 AM, Antoine Zimmermann wrote: > For me, the problem of scope goes beyond blank nodes. > > It would be good to be able to say (in a standard way), for instance: > > 1) within my scope, this graph has to be interpreted with a unique name > assumption (I know the things in my local system, I do not identify them > twice) > 2) within my scope, this graph has to be interpreted with a closed world > assumption (I know everything about my things in my local system, if you > can't conclude a statement is true from my scoped graph, you can > conclude it is false) > 3) within my scope, bnodes are interpreted as constants (so, the graph > "ex:s ex:p _:bn1, _:bn2" is effectively not equivalent to "ex:s ex:p > _:bn3") > 4) within my scope, I abide by the RDFS entailment regime (or OWL 2 RL; > or OWL RDF-based semantics; or RDF recognising xsd:duration, > geo:wktLiterals; etc.) - which means I may not agree with other semantic > restrictions made by other standard regimes > 5) within my scope, this specific set of inference rules hold (such as, > that owl:sameAs is reflective and symmetric, but not necessarily > transitive) - if you consume my data, you can assume what you want, but > you've been warned! > > and possibly more: > > 6) within this scope, the triples are assumed to be truthfuly describing > the world as it was at this specific time point / time intervale > 7) within this scope, the triples are not trustworthy (or only trusted > to a certain degree) > 8) within this scope, the graph describes Mr X's opinion > etc. +1. I like this idea a lot. And it seems to me that if we had a standard way to indicate a semantic extension within a particular scope, such a mechanism could address nearly all of these needs. https://github.com/w3c/EasierRDF/issues/25 David Booth > > > Any real life application that consumes an open set of data from the Web > has, in any case, to define its scoping mechanism. There's much research > work showing that RDF is used all over the web with different > assumptions: assumptions regarding bnodes, regarding unique names, > regarding closed world, even regarding the meaning of normative terms > like rdfs:domain, rdfs:range, owl:sameAs; regarding literals as well. If > one ever wants to build an application that consumes Web data at large, > one has to put barriers to the normative semantics of Semantic Web > standards. Unfortunately, the standards do not make this explicit, and > people have to experience the big slap in the face of Web inference > before working out yet another scoping mechanism (or just give up and do > GraphQL...). > > > > --AZ > > > Le 10/12/2018 à 00:43, David Booth a écrit : >> On 12/8/18 2:32 AM, Patrick J Hayes wrote: >>> >>> >>>> On Dec 5, 2018, at 3:41 PM, David Booth <david@dbooth.org> wrote: >>>> >>>> On 12/3/18 4:38 PM, Patrick J Hayes wrote: >>>>>> Bnodes introduced to encode >>>>>> structures like n-ary relational assertions, or lists, or some >>>>>> complicated piece of OWL syntax, should have a very narrow scope >>>>>> corresponding to the exact boundaries of those structures, and >>>>>> hence should be ‘invisible’ from outside (which is why it is fine >>>>>> to make them vanish in a higher-level syntax using [ ] or ( ).) >>>>>> >>>>>> Ideally, RDF2 should provide for these structures directly, but >>>>>> maybe we can get the benefit with a relatively tiny step, just by >>>>>> having a syntax for RDF which has explicit scoping brackets. >>>> >>>> Interesting idea, and I can see it being useful for RDF streams or >>>> very large RDF datasets -- to enable blank node labels to be safely >>>> reused without collision -- but I am also curious: >>>> >>>> 1. How would you envision scope names being used? >>> >>> I was thinking of them simply as a lexical trick to allow bnodes to >>> be ‘bound’ at a particular scope. >> >> Actually I was wondering about use cases. What additional use cases >> do you think scoped bnode would address, other than the two that I >> mentioned above? >> >> Thanks, >> David Booth >> >
Received on Wednesday, 12 December 2018 22:28:00 UTC