Re: on property paths in SHACL

Dear Peter,

Thank you for your feedback on property paths.
Can you please check if you have further comments on this section?
We tried to also cover other comments you had on the equivalency of
property paths

http://w3c.github.io/data-shapes/shacl/#path-syntax

Best regards,
Dimitris

On Fri, Sep 23, 2016 at 5:25 PM, Peter F. Patel-Schneider <
pfpschneider@gmail.com> wrote:

> Following up one of the recent responses to my comments on Shapes
> Constraint
> Language (SHACL) lead me to look at how property paths work in Shapes
> Constraint
> Language (SHACL), W3C Editor's Draft 22 September 2016.
>
>
> The definition of property paths includes:
> "A valid SHACL property path p is represented by an IRI or a blank node
> that
> can be correctly traversed recursively using the following rules."
>
> The use of "recursively" is incorrect here.  There is no need to use a
> recursive process here at all.  The use of "traversed" is incorrect here.
> There is no need to traverse anything here at all.
>
> A much better wording is
> "A valid SHACL property path p is represented by an IRI or a blank node
> that
> satisfies the following conditions."
>
> It is possible for a node to both be a valid property path and an invalid
> property path, which does not seem to make any sense.
>
> It is possible for a non-invalid property path to satisfy both rule 4 and
> one of the other rules. What happens then?
>
> The definition of property paths contains a use-mention error.  A property
> path is represented by a node but then the path itself is treated as if it
> were a node in an RDF graph.
>
> As a not-invalid property path cannot have multiple outgoing edges it is
> hard to add extra information to property paths.
>
> The SPARQL path resulting from rule 2 is not defined.  As well, "value of
> path" is not defined.   It appears that the intent is that p itself is an
> RDF list, but that would make p be an invalid SHACL property path.
>
> The entire section needs to be completely rewritten.
>
>
>
> Peter F. Patel-Schneider
> Nuance Communications
>
>


-- 
Dimitris Kontokostas
Department of Computer Science, University of Leipzig & DBpedia Association
Projects: http://dbpedia.org, http://rdfunit.aksw.org,
http://aligned-project.eu
Homepage: http://aksw.org/DimitrisKontokostas
Research Group: AKSW/KILT http://aksw.org/Groups/KILT