Re: Proposal for ISSUE-1

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If SHACL needs to determine whether a node belongs to an RDFS class and also
uses some kind of reasoning over RDFS subclass links then the only clean way
forward is to use RDFS reasoning.

It appears, however, that support for RDFS reasoning may be somewhat lacking
in major SPARQL engines.  If so, then there may be a regrettable need to
support other mechanisms in SHACL systems that use SPARQL engines.

One possible semi-clean way forward is to:
1/ For certain SHACL constructs perform RDFS class membership inferencing by
the SHACL system itself as needed.
2/ Add a construct to SHACL that states which kind of inferencing is
required.  If this inferencing cannot be effected, then the SHACL engine
would signal a fatal error and not do any constraint processing.
The kinds of inferencing would include none, RDF entailment, and RDFS
entailment.


Having the SHACL system perform RDFS class membership reasoning itself does
not necessarily mean that the SHACL system would have to take a data graph
and add entailed triples to it.  The SHACL system could modify its emitted
SPARQL queries so that they do the right thing.  (To make this actually
easily doable SHACL might be defined as not working completely correctly on
data graphs that have subproperties of rdfs:subClassOf.)


peter

PS:  Inconsistency of data graphs could be handled in the same way that it
is handled in SPARQL entailment regimes.

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Received on Thursday, 21 May 2015 14:09:19 UTC