- From: Fabien Gandon <Fabien.Gandon@sophia.inria.fr>
- Date: Thu, 29 Apr 2004 19:20:53 +0200
- To: public-swbp-wg@w3.org
My 2 (euro) cents... ;-) AR: "I think the above indicates that of all the problems we could have started for on best practice, 'Classes as Values' is the perhaps most difficult and problematic. I agree but IMHO some of these are not directly relevant to "Classes as Values" and should really be out of the scope of the design pattern, possibly referenced in a "see also section". In particular vii) and ii) AR: " ii) 'Born Free' a book about a particular lion" This is a classical case of linking two individuals with no special problem as you underline latter in your message. AR: "vii) That 'John' is credited as the author of the class Lion in a KB (As a statement about John). (...) NB we don't have a distinction between 'class' and 'concept represented by the class' available to us. The author of the class and the person who first described the species are clearly different." My opinion is that this is a different problem: this statement is not about the class but about the statement declaring the class. Therefore I would rather expect something like: <rdf:Statement rdf:about="#LionDeclaration"> <rdf:subject rdf:resource="&example;#Lion"/> <rdf:predicate rdf:resource="&rdf;type"/> <rdf:object rdf:resource="&rdfs;Class"/> <dc:creator rdf:resource="&company_staff;#John"/> </rdf:Statement> AR: " v) A reference to the 'Lion Genome' - (plausible for Dog, Cat, etc. and no doubt eventually for Lion)" Here I think the problem is rather at the inference level: there is a book referencing an object "Genome" that belongs to the Specie "Lion", then we are missing an inference saying that when a document is about an object directly attached to a species then the document is about the species. AR: "(...) the semantics of any negated queries (there is no explicit negation in RDF) will be closed world" I am by no mean an expert here but my opinion is that the "not" operator should may be split in two: a "naf" operator implementing "negation as failure" i.e. the "there does not exist a statement saying that..." (with all the non monotonic problem that comes with it) and the full negation operator "not" saying that it can be proved that the statement is false for instance if "Lion" and "Whales" are disjoint classes then it can be proved that a given instance of lion cannot be a whale. AR: "(...) A is immediately in OWL-Full, yet neither A nor B expect to perform any inferences using the information in C's ontology. If the rest of A's ontology conforms to the restrictions on OWL-DL, it seems perverse not to apply OWL:DL semantics and reasoners." I think I agree with you here but I am probably misunderstanding your point. I personally don't quite understand the danger in referencing an OWL Class as long as you are not talking about the class (ex: adding to its description) etc. If the reference is only used to qualify an instance (ex: give the subject of a book) then in what respect is it more dangerous than the classical typing relation which also qualifies an instance with reference to a class? Fabien. -- "Stories are our dreams. And our dreams are our life." -- Tim Burton. ____________ |__ _ |_ http://www-sop.inria.fr/acacia/personnel/Fabien.Gandon/ | (_||_) INRIA Sophia Antipolis - ph# (33)(0)4 92 38 77 88
Received on Thursday, 29 April 2004 13:22:14 UTC