- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Thu, 15 Nov 2001 12:56:39 -0600
- To: Patrick.Stickler@nokia.com
- Cc: w3c-rdfcore-wg@w3.org
> > ...The other proposals (S, DC and oldX=URV) don't need >> this complication, however, since they can assume tidiness on literal >> nodes as well as urirefs. > >Can someone please point me to the most concise, prose definition >of tidiness as it relates to the graph? Sorry, local jargon. I invented the term in the MT document, by defining an RDF graph to be 'tidy' if had no duplicated names, so each uriref or literal occurs only on a single node. (At that time I was assuming (naively) a U-style treatment of literals. ) Since then it has also been used to refer to the condition that triples are not duplicated in any graph, for example. The reason for having such a term is that forming the simple union of two graphs can produce a non-tidy graph, so one has to get explicit about the tidying process (ie the merging of nodes with the same label to create a tidy merged graph.) When we started taking literals more seriously, some ways of treating them (the P(++) ways) require that different occurrences of the same literal may have different meanings, so it is no longer appropriate to insist on tidiness for literal nodes. In fact, this is one way that the P(++) proposals (and I think the X, though I'm not sure) can be distinguished from the U/S/DC proposals, in that the latter will work with graphs that are tidy on literals, while the others will not. So this decision has consequences even for the graph syntax. 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, 15 November 2001 13:56:18 UTC