- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Sun, 24 Feb 2002 19:28:49 -0600
- To: "Seth Russell" <seth@robustai.net>
- Cc: www-rdf-comments@w3.org
>From: "Tim Berners-Lee" <timbl@w3.org> > >[[ >I understand that current RDF does not allow subjects to be literals. This >is acceptable as a response at this stage, because of the damage to the RDF >syntax to try to fix it. >]] > >I don't understand this "damage" to syntax. What are the problems with just >using something like "rdf:aboutLiteral" instead of "rdf:about" where the >subject is a literal? I gather that there is no problems with the >semantics of using literals for subjects. There are some syntax issues. One problem arises as follows. Imagine that we allow literals as subjects, and we have the following kind of situation aaa --ppp---> "13" ---qqq---> bbb ccc --rrr-->"13" ---sss--> ddd Now if we have 'tidy' literals - which many people want to, for technical reasons - then those two literals have to be the same node; and then we have a graph with five nodes consisting of a literal with two triples coming 'into' it and two triples coming 'out of' it, but no way to tell which goes with what. If these were blank nodes we could just use two nodes, but the literal labels will *force* the nodes to be merged (if nodes are tidy). Im not saying this would be fatal, but it would create some new problems. And there are also some issues with using the Ntriples syntax with literals as subjects. And, of course, XML introduces yet more syntactic conditions. So one way and another, it is a bit of a mare's nest. 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 Sunday, 24 February 2002 20:28:57 UTC