- From: Jeremy Carroll <jjc@hpl.hp.com>
- Date: Fri, 20 Jun 2003 09:41:28 +0300
- To: www-webont-wg@w3.org
This includes my review of the changes to the annotation semantics. I conclude that some WG telecon time should be spent on this and the "layering bug?" thread. Jeremy: > Does > > Class( <foo> annotation( <a> <bar> ) ) > AnnotationProperty( <a> ) > Class( <bar> ) > > entail > > AnnotationProperty( <a> ) > Class( <foo> annotation( <a> individual() ) ) Peter: >I propose to fix this by modifying the direct semantics to admit ``junk'' >elements of the domain, i.e., elements of the domain that are not >individuals. This makes the direct semantics more ugly, but more like the >RDF semantics. >One side effect would be that Jeremy's entailment above would not hold, >because <bar> would not have to be an individual. Minutes June 5 http://lists.w3.org/Archives/Public/www-webont-wg/2003Jun/0050. >ACTION: Jeremy Carroll - review proposed change to direct semantics that > handles annotations better. S&AS editors draft section 3 > EC(owl:Thing) = O ⊆ R, disjoint from LV appears as the definition of O, but the first use of O is higher in the table. I found this somewhat confusing. However, as far as I can tell, the changes are doing what you wanted ... but ... while > Class( <foo> annotation( <a> <bar> ) ) > AnnotationProperty( <a> ) > Class( <bar> ) > does not now > entail > > AnnotationProperty( <a> ) > Class( <foo> annotation( <a> individual() ) ) we have that T( > Class( <foo> annotation( <a> <bar> ) ) > AnnotationProperty( <a> ) > Class( <bar> ) ) OWL Full entails T( > AnnotationProperty( <a> ) > Class( <foo> annotation( <a> individual() ) ) ) because the individual() item is transformed into a bnode (with type owl:Thing?) and the type triple is trivially true, so that the OWL Full contentful part is: <foo> <a> <bar> . entails <foo> <a> _:b . which is true in RDF. This seems to be another instance of the "layering bug?" to which you say: > if an entailment holds in OWL DL then it holds in OWL Full, > not vice versa. IMO it is worth highlighting this to the WG, and ensuring that the other documents capture this. for example, TEST needs to change to make it clear that an OWL Full consistency checker and an OWL DL consistency checker may get different results on a DL document. That's not good. Jeremy
Received on Friday, 20 June 2003 03:41:36 UTC