- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Mon, 8 Oct 2001 17:11:40 -0500
- To: Sergey Melnik <melnik@db.stanford.edu>
- Cc: w3c-rdfcore-wg@w3.org
Sergey, sorry this slipped off my screen. >I'm thinking of how composite literals may be potentially introduced in >the MT document, and what the implications of that could be. > >A first shot at MT of datatyping could be this: assuming that literal >constants are pairs of kind (URI, unicode string), let the URIs >(resource constants) be mapped to resources as before using function IS. >Additionally, one could define a mapping IDT from IR into the powerset >of LV that maps each datatype-resource to its extension, namely, the set >of all literals that correspond to this datatype. For example, if X001 >is an interpretation of resource constant >[http://www.w3.org/2001/XMLSchema-datatypes, integer], so the extension >of the datatype XOO1, i.e. IDT(X001), would include all "integer" >literals. If I follow you here, the literal itself would be rather like a pair of a URI and a special kind of property whose value is the class of literal values that this URI might have. But what determines the actual literal value? Eg suppose I write aaa foo <bbb, [http://www.w3.org/2001/XMLSchema-datatypes, integer]> . then the interpretation I(bbb) isn't itself an integer, right(? Or is it? If so, what ensures that it is?) IDT([http://www.w3.org/2001/XMLSchema-datatypes, integer]) is the set of integers, OK. But what is the thing that is the value of the property IEXT(I(foo)) on I(aaa)? Sorry if I'm being dense. >Some general comments on MT: > >I very much welcome your move towards a cleaner separation between RDF >and RDFS. I think it maybe worth it to emphasize the point that other >languages (besides RDFS) can be layered on top of RDF, and to illustrate >how their semantics can be defined incrementally (e.g., using the >I-mappings of the underlying languages). In this light, RDFS-MT could be >presented as a proof-of-concept of how this layering is done. That is how it is meant at present. I will try to state this more clearly, though I want to be careful not to claim the moon. Also, Peter P-S is re-writing the DAML MT to be a further extension in the same style, so that will help make the same point. >A minor comment: could you make sure that all symbols are introduced in >the same section (or are summarized in a table)? For example, most of >the definitions are in 1.4, but LV and XL appear first in 1.3. OK, I will fix this. >Another >issue, which I raised in my previous email, is a consistent naming of >constants vs. individuals in the domain of discourse (e.g. resource >constant and literal constant instead of URI and literal, or something >like this). We are still arguing about this on that other thread. 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 Monday, 8 October 2001 18:11:45 UTC