- From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
- Date: Sun, 20 Jul 2014 07:54:19 -0700
- To: Simon Spero <sesuncedu@gmail.com>
- CC: Kendall Clark <kendall@clarkparsia.com>, Sandro Hawke <sandro@w3.org>, Eric Prud'hommeaux <eric@w3.org>, "Dam, Jesse van" <jesse.vandam@wur.nl>, Jerven Bolleman <jerven.bolleman@isb-sib.ch>, "public-rdf-shapes@w3.org" <public-rdf-shapes@w3.org>, Evren Sirin <evren@clarkparsia.com>, Jose Emilio Labra Gayo <jelabra@gmail.com>, Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>
This does seem rather complex. I don't see why you need to know all this stuff just to say, for example, that people have names and students have universities. peter On 07/20/2014 06:05 AM, Simon Spero wrote: > On Jul 20, 2014 5:05 AM, "Peter F. Patel-Schneider" <pfpschneider@gmail.com > <mailto:pfpschneider@gmail.com>> wrote: > > > > It is very hard to see how ShEx constraints can be associated with > instances of RDFS types. I view the ability to associate constraints with > instances of types as the most important aspect of a constraint system, hence > my questions about how this can be done in ShEx. > > There's an obvious approach, but I don't think it is right? > > If only a single pattern may match a predicate then there can only be a single > pattern matching rdf:type. > > If the entire class hierarchy is known at the time that the pattern is > created, then a pattern can be created as a set of disjuncts. > For each acceptable subclass there would be a disjunct for each member S of > the power set of superclasses of that subclass, with a value set for rdf:type > consisting of the subclass plus all members of S, with a fixed cardinality > on the pattern equal to the size of the value set. > > As long as the matching is against a graph, so that duplicate triples are not > present, this should match all and only the desired types. > > Fewer patterns could be used if all super classes are required to be present > (one pattern for each distinct set of superclasses of an acceptable class that > does not contain that any acceptable class). The value set for each pattern > would contain the superclasses, plus each acceptable class for which those > classes are the non-acceptable superclasses. The minimum cardinality would be > one more than that of the set of superclasses. > > If inferencing is not allowed, and no superclasses that are not sufficient for > a match are allowed, then a value set of just the sufficient classes, with > minimum cardinality 1 would suffice. > > This seems too complicated to be the right way, so I may have missed something. >
Received on Sunday, 20 July 2014 14:54:48 UTC