well-formed Shape Expressions Schemas

• From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
• Date: Tue, 17 Nov 2015 06:03:28 -0800
• To: Iovka Boneva <iovka.boneva@univ-lille1.fr>
• Cc: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
• Message-ID: <564B33B0.6020209@gmail.com>

It appears to me that the definition of well-defined Shape Expression schemas
in http://arxiv.org/abs/1510.05555 is unduly restrictive.

It rules out, for example

<A> { ex:p @<A> }

<B> { ex:q !@<A> }

even though this schema is well behaved, i.e, it has a unique maximal model.

So, why not allow any set of shape definitions that has stratified negation?
Stratified negation is a well-studied notion and evaluation techniques for
stratified negation are well known and should be easily adaptable to Shape
Expression schemas.



peter


PS:  I think that you meant to say "acyclic directed graph" in Definition 1.

Received on Tuesday, 17 November 2015 14:04:00 UTC