- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Thu, 27 Sep 2001 22:49:00 -0500
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
- Cc: www-rdf-logic@w3.org
>I am concerned that this model theory locks RDF into a particular >way of interpreting literals, namely that the interpretation of a literal >can be completely determined from its label, using a fixed mapping to >literal values. (One way to do this would be to require that literals >include typing information, perhaps looking something like INT(10) or >STRING(10).) That is not the intention, and I don't think it can be reasonably inferred from the text. > >While this may seem to be the only way to go, consider the case with XML >Schema, where the interpretation of a ``literal'' depends on typing >information that is specified elsewhere. In XML Schema, you don't know >what an element means unless you have acces to the schema. I think that >this translates to the following in RDF. The interpretation of a literal >in RDF+Schema depends on some typing information for the literal, which >need not be specified with the literal. I think that if RDF is to >incorporate (aspects of) XML Schema it should be prepared to allow this >sort of separate typing. > >Comments? My understanding of the model theory is that it does allow this, though I agree that could be stated more clearly. The comment in section 1.2 (3rd paragraph) is intended to convey the idea that literals may turn out to be quite complex entities, perhaps partly defined by a schema, for example; NO assumptions are supposed to be made about the nature of literals, other than they are SOMEHOW syntactically distinguishable from URIs. That distinguishability may depend on any computational task performed by any lexicalizer or parser, however complex it may be. In particular, a 'literal' in the sense used by the model theory may be more complex than (and in any case different from) an xml:literal. Hope this helps. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Thursday, 27 September 2001 23:49:03 UTC