- From: Seth Russell <seth@robustai.net>
- Date: Wed, 24 Oct 2001 18:02:59 -0700
- To: "Pat Hayes" <phayes@ai.uwf.edu>
- Cc: <www-rdf-logic@w3.org>
From: "Pat Hayes" <phayes@ai.uwf.edu> Sandro Hawke: Something we might like to add to RDF, to make it more expressive, is logical negation. How would you extend RDF's syntax to handle it? Lay on another language, which is interoperable with RDF. Say in an RDF graph syntax. PH: Why in an RDF graph syntax? (What is so special about RDF? Its one among thousands of possible notations, and its not a particularly good one. The limitations of simple graphs as a notation have been known for about a century, so why would we want to deliberately go back to the stone age to find a basis for the world wide web? ) SR: I would like to know specifically what those limitations are ... I have not found any. PH: No way to indicate scope or variable bindings, chiefly. SR: Well actually there is if you will allow that a scope of a variable can be specified by a set of statements and that statements themselves have identity. PH: OK, no way to indicate a set of statements. Same thing. SR: Well actually there are two ways to do that. [snip ..] PH: Neither of these is possible in RDF, however. RDF uses triples, not quads; it has no mechanism or notation for attaching identifiers to statements; and it requires arc labels to be urirefs, not pairs of anything. Of course there are extensions of RDF in which all manner of things can be written, but this is the RDF-logic list, not the RDF++-logic list. SR: Seems we have come full circle here and cannot extend RDF to a graph syntax that is interoperable with RDF because of the limitations of simple graphs, but cannot remove those limitations because then it would not be RDF. .... wiggy woggy woo ... Seth Russell
Received on Wednesday, 24 October 2001 21:04:50 UTC