- From: pat hayes <phayes@ai.uwf.edu>
- Date: Sun, 26 Jan 2003 09:52:36 -0700
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
- Cc: www-rdf-comments@w3.org, w3c-rdfcore-wg@w3.org
>I believe that untyped literals do not work correctly in the RDF model >theory. The semantic constraint on rdfs:Literal is, from Section 3.3 > > ICEXT(I(rdfs:Literal)) is a subset of LV > >However, the denotations of untyped literals are only required to be >in LV. Therefore the denotation of "a" is not necessarily in >ICEXT(I(rdfs:Literal)). >This situation has observable consequences. For example > ex:foo ex:rel "a" . >does not RDFS-entail > ex:foo ex:rel _:x . > _:x rdf:type rdfs:Literal . > >The situation is made even stranger in datatyped interpretations. If >there is a datatype whose value spaces includes the string "a", then >entailment over this datatype has the above entailment. > That is true. This was a deliberate decision, but it could be changed. The essential change is to require that ICEXT(I(rdfs:Literal)) = LV, rather than being a subset of LV. In this case it would probably be better to also make LV part of the interpretation and add semantic conditions on it. Unless anyone objects, I will make this change in the final publication version. The effect of this can be summarized by saying that untyped literals will then be treated like typed literals with a 'blank' datatype which has the identity mapping as its lexical-to-value mapping. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes s.pam@ai.uwf.edu for spam
Received on Sunday, 26 January 2003 11:51:24 UTC