From: Peter F. Patel-Schneider (pfps@research.bell-labs.com)
Date: 10/10/01
From: Pat Hayes <phayes@ai.uwf.edu> Subject: model theory and literals Date: Wed, 10 Oct 2001 12:36:24 -0500 > Peter, after my mini-epiphany during the telecon yesterday, I had an > even better one :-). I think that there is a very tiny, if > unconventional, change to the RDF MT which will allow it to > accommodate smoothly to your (or anyone else's) proposed treatment of > literals: simply say (with some explanatory prose :-) that the XL > mapping is a fixed mapping from literal TOKENS to literal values. > That is, it allows one occurrence of <whatever>05</whatever> to > denote an integer and another one to denote a string, just as long as > they each denote the same thing in every interpretation. Hmm. Interesting, sneaky, and underhanded! I like it. Well, actually, I don't think that it works. > This allows > both the case where every literal is simply a string which denotes > itself, and it also allows the extreme other case where an elaborate > external datatyping process assigns special values in all sorts of > ways. However, it does insist that each literal label token has a > fixed interpretation; it doesn't tolerate ambiguity of any > *particular* literal label. I don't want to allow that kind of > ambiguity. See below. > This will leave entirely mysterious how anyone or anything could > determine what the actual denotation of any particular literal token > actually is, of course. That is assumed to be done somehow, but is > outside the scope of the MT itself. > > With this change in wording, the actual equations can remain as they are. > > Would that be sufficient flexibility for you, along with allowing IR > to consist of both resources and literal values, so that rdfs:Literal > doesn't force literal values to be resources? The problem is that I want (for what I consider to be good reasons, see my posting to www-rdf-comments) to be able to have that John age 05 . has several models, some which have (this) 05 be an integer and some which have it be a string. > Pat My current thinking is that nodes with literal labels are treated much like nodes with no labels, except that their interpretation is restricted by XL. peter
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