Re: type and instance and subclass in SHACL documents

On Mon, Mar 21, 2016 at 8:15 PM, Peter F. Patel-Schneider <
pfpschneider@gmail.com> wrote:

> I don't think that this helps at all.  In fact, all that it does is further
> obfuscate the issue.  The issue is that the wording needs to be clear that
> in
>
>   sh:shape rdf:type my:Shape .
>   my:subClassOf rdfs:subPropertyOf rdfs:subClassOf.
>   my:Shape my:subClassOf sh:Shape .
>
> my:Shape is not a SHACL shape, but that in
>
>   sh:shape rdf:type my:Shape .
>   my:Shape rdfs:subClassOf sh:Shape .
>
> it is.
>
> There are many cases where the SHACL notion of subclass, instance, typing,
> etc., diverges from the common definition of these notions.
>

I think the only actual case is sh:scopeClass and sh:class, sh:classIn,
meaning how shacl engines apply the shapes in a data graph.
The rest of the cases can be valid, one just needs to enable RDFS inference
on the shapes graph to achieve that.

R2RML is a very similar language to SHACL.
an R2RML graph (similar to the shacl graph) is applied on a relational
database (similar our data graph) and produces RDF (our validation results).

@Richard, you are an editor and implementer of R2RML, can you comment if in
D2RQ e.g. an instance of rr:TriplesMap is recognized is a similar example
as Peter wrote above?
Note that R2RML does not have an RDFS disclaimer section so maybe we can
get some ideas on how they do things, try to follow their approach and put
emphasis on sh:scopeClass, sh:class and sh:classIn.

Dimitris


>
> peter
>
>
> On 03/21/2016 02:05 AM, Dimitris Kontokostas wrote:
> > Hi Peter, I did some research on other w3c specs regarding the term
> instance.
> >
> > if we changed occurrences of instance from e.g.
> > "shapes are the instances of sh:Shape" to
> > "sh:Shape is the class of all shapes"
> > would this be fine from your side?
> >
> > Some cases like sh:class and sh:classScope would need extra care of
> course.
>