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Comment on Last Call Working Draft of RDF Semantics document concerning untyped literals

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 24 Jan 2003 17:12:35 -0500
To: www-rdf-comments@w3.org
Message-id: <3E31BA53.7060300@research.bell-labs.com>


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.
Received on Friday, 24 January 2003 17:14:02 GMT

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