- From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Date: Wed, 19 Sep 2001 18:17:08 +0100
- To: Pat Hayes <phayes@ai.uwf.edu>
- Cc: w3c-rdfcore-wg@w3.org
At 02:27 PM 9/18/01 -0500, Pat Hayes wrote: >At last the model theory is in readable form, at > >http://www.coginst.uwf.edu/~phayes/RDF%20MT-currentdraft.html Pat, I have a couple of small comments/questions about this, and a more substantial issue (the final point below). - the document variously uses the terms URI, uriref, <uriref> to mean something like "URI-plus-optional-fragment". Maybe we could coin a term for this and use it consistently? - Section 5: I thought this was great; very neat. Would I be correct in thinking that the schema-closure of any graph satisfies the Strong Herbrand Lemma. Hmmm.. as stated, I think this is trivially true, as the lemma is stated in terms of satisfaction, which is not affected by the new inferences based on schema constructs. I think what I want to suggest is this version of the lemma: The schema-closure of any RDF graph has an RDFS interpretation that satisfies the graph and does not satisfy any ground triple not in the graph. >>> the substantial issue: - Section 5: I think there may be a problem with the schema lemma, in { S1, S2 } entails E: S1: x:a rdfs:subClassOf x:b . S2: x:b rdfs:subClassOf x:c . E: x:a rdfs:subClassOf x:c . Schema closures: S1: x:a rdfs:subClassOf x:b . rdfs:subClassOf rdf:type rdf:Property . rdf:type rdf:type rdf:Property . rdf:Property rdf:type rdfs:Class . rdf:Property rdfs:subClassOf rdfs:Resource . rdfs:Class rdf:type rdfs:Class . rdfs:Class rdfs:subClassOf rdfs:Resource . rdfs:Resource rdf:type rdfs:Class . rdf:type rdf:type rdfs:Resource . rdfs:Class rdf:type rdfs:Resource . : (+ others not including x:a or x:b) S2: x:a rdfs:subClassOf x:b . rdfs:subClassOf rdf:type rdf:Property . rdf:type rdf:type rdf:Property . rdf:Property rdf:type rdfs:Class . rdf:Property rdfs:subClassOf rdfs:Resource . rdfs:Class rdf:type rdfs:Class . rdfs:Class rdfs:subClassOf rdfs:Resource . rdfs:Resource rdf:type rdfs:Class . rdf:type rdf:type rdfs:Resource . rdfs:Class rdf:type rdfs:Resource . : (+ others not including x:a or x:b) Applying the interpolation lemma, the merge of s-closure(S1) and s-closure(S2) does not contain E as a subgraph. But, intuitively S1 and S2 together should entail E. The problem, I think, is that the schema closure is applied before doing the graph merge. I think the lemma should be something like this: S s-entails E iff the schema-closure of the merge of members of S entails E. #g ------------------------------------------------------------ Graham Klyne MIMEsweeper Group Strategic Research <http://www.mimesweeper.com> <Graham.Klyne@MIMEsweeper.com> ------------------------------------------------------------
Received on Wednesday, 19 September 2001 13:22:36 UTC