- From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
- Date: Mon, 7 Mar 2016 15:00:03 -0800
- To: Holger Knublauch <holger@topquadrant.com>, public-data-shapes-wg@w3.org
On 03/07/2016 02:36 PM, Holger Knublauch wrote: > On 8/03/2016 1:51, Peter F. Patel-Schneider wrote: >> On 03/06/2016 08:46 PM, Holger Knublauch wrote: >>> Thanks for the feedback, Peter. I have tried to address it here: >> [...] >> >>> On 7/03/2016 6:59, Peter F. Patel-Schneider wrote: >>>> General >> [...] >> >>>> It is not sufficient to say in 1.1 that SHACL has unique versions of types >>>> and instances. These notions are in very widespread use. Each time that >>>> SHACL deviates from the common, accepted W3C practice it should be called >>>> out, e.g., "SHACL type" or "SHACL instance". >>> I hope this doesn't need to be repeated each time as this may render the >>> document harder to read. Furthermore, the terms "SHACL type" and "SHACL >>> instance" would first need to be formally defined too. >>> >>> Instead, I suggest we should define what "type", "instance" and "subclass" >>> mean in the remainder of the document. I have put a corresponding terminology >>> block at the end of section 1.1 >> This is inadequate. >> >> SHACL uses RDF graphs and RDFS vocabulary. There are already definitions of >> type and instance and subclass that come from RDF and RDFS. SHACL needs to >> differentiate its version of type and instance and subclass from these >> dominant notions and this can only be reliably done by qualifying them each >> time they appear in formal SHACL documents. >> >> Alternatively the SHACL document could use different words for these >> relationships or could restrict the inputs that it handles so that it uses the >> dominant versions of type and instance and subclass. > > My interpretation of the situation is > > - RDF and RDFS define the IRIs of vocabulary terms rdf:type and rdfs:subClassOf > - terms like subclass, type and instance already existed before RDFS and carry > intuitive meaning In some contexts yes. Not in a context RDF graphs and rdfs:subClassOf are present. In this context, RDF and RDFS type, instance, and subclass are in play so different meanings of these terms need to be called out explicitly. > - there is no need to over-complicate a situation that is already clear to > most readers I don't see how it can be clear to readers if the document itself is incorrect in places. > The only difference between our definitions of the terms is that you think > that subclassing must always require inferences (domain, ranges etc). Not just subclassing, but also typing and instance. SHACL uses neither the RDF nor the RDFS meaning of both these terms. > I > believe these concepts are orthogonal. Some rdfs:subClassOf triples may be the > result of inferencing, but it doesn't matter to SHACL where they came from. As > long as we make this clear in the beginning, I hope we can keep the document > intuitive and not over-complicate it. Right now the document is hard to read. I have to continually remind myself that type, instance, and subclass have new meanings, to the point where I do not catch places that are incorrect in the document. > Holger peter
Received on Monday, 7 March 2016 23:00:46 UTC