- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Tue, 29 Jul 2003 08:00:39 -0400 (EDT)
- To: phayes@ihmc.us
- Cc: w3c-rdfcore-wg@w3.org, www-rdf-comments@w3.org
From: pat hayes <phayes@ihmc.us> Subject: semantics update Date: Mon, 28 Jul 2003 23:29:18 -0500 > http://www.ihmc.us/users/phayes/RDF_Semant_Edit_Weak.html > > now reflects the post-Beckett/PFPS/Carroll editing and all subsequent > decisions. It has a slightly different look/feel (colors, table > titles etc) , updated references (though if anyone has any complaints > about any of those please feel free to correct me) and some more > anchors and internal links. Ive made the text links slightly visible > by messing with the background color, but if people don't like this > its easy to tweak it in some other way. > > Text changes since the last version are in red. They include > rewriting of the definition of 'merge', some minor rewordings to > clarify meanings more carefully, and putting back the definition of > 'vocabulary entailment' which had gotten lost somewhere (its now > section 2.1 and has several links to it) and references to blank node > *identifiers* in the statement of the rules (suggested by Dave). Also > the dire warning about rdf:value (section 3.2.4) has been made less > dire, also suggested by Dave. > > Significant changes are that XMLiteral values are stated explicitly > to be distinct from character strings (defn of RDF interpretation, > section 3), and the equivalence between plain literals and xsd:string > typed literals is noted explicitly and an inference rule provided > (end of section 7.4). The wording of the Lbase translation has been > slightly altered to fit that last change also. > > The change list has been rewritten and is at the end. > > Pat > > PS. Peter, I believe this now addresses all your concerns. It may be that the changes do address all my concerns, I don't have time to check just now, and may not for at least a week. However, during the quick check I just made I found some remaining concerns. The first thing I checked was the list of post-last-call changes. I noticed that several changes that result in changes to RDF(S) entailments are not mentioned as substantial changes. The change making LV = ICEXT(I(rdfs:Literal)) means that ex:foo ex:rel "a" . rdfs-entails ex:foo ex:rel _:x . _:x rdf:type rdfs:Literal . whereas it does not in the last call semantics. This was pointed out in http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0085.html. The change to datatyping in RDF makes many changes to D-entailments. In the last call semantics, there were few D-entailments, as there was no way to impose connections between typed literals and datatypes. For example, ex:foo ex:rel "1"^^xsd:decimal . did not xsd-entail ex:foo ex:rel "01"^^xsd:decimal . in the last call semantics because xsd-interpretations did not require that I(xsd:decimal) be the xsd:decimal datatype. The change requiring non-emtpy datatypes, although it technically does not affect any entailments, changes the permissable set of RDF datatypes, and thus forms a significant change to the RDF datatyping design. Without a comprehensive list of such changes, I do not view the RDF Semantics document as complete. Problems arise in the description of other changes. I can't imagine how the significant changes to the mapping to Lbase can be listed under ``The following changes do not effect [sic] the technical content.'' The change to lists doesn't affect any entailments that I can see. In fact, the it doesn't change anything at all with respect to the semantics, even the set of RDF graphs that are the result of RDF/XML parsing. The change to datatypes is not needed for compatability with OWL. It is instead needed because the last-call treatment of datatypes didn't work right. Peter F. Patel-Schneider Bell Labs Research Lucent Technologies PS: I also noticed a typo in 4.3 - Rdf -> Rdfs
Received on Tuesday, 29 July 2003 08:00:48 UTC