- From: Bijan Parsia <bparsia@isr.umd.edu>
- Date: Wed, 6 Apr 2005 21:45:39 -0400
- To: Paul Gearon <gearon@itee.uq.edu.au>
- Cc: www-rdf-logic@w3.org
On Apr 6, 2005, at 8:11 PM, Paul Gearon wrote: > > I need to respond to what everyone has said about cardinality (thanks > for the responses!), but I thought I'd better write up something on > the approach that I've been taking. That may help me clear up some of > my fundamental misconceptions, and ease the rest of my process of > understanding. > > I'll confess that my terminology may not always be appropriate. > Terminology can be confusing, as different sources define certain > concepts with subtle differences. For instance, one source I have > defines consistent expressions as being true under at least one > interpretation, Another way of putting it is "having one model. > while another source defines it as "Having no contradictions." These > end up being equivalent for most systems, All classical systems (hmm, if "Classical" doesn't include intuitionism, then this is too narrow). Paraconsistent system, of course, are different. > but there are subtle differences (according to one professor I know), > that I only have a vague grasp of. I'd be interested in a pointer to what that professor is talking about. In any case, for many practical purposes (and certainly for RDF), it's ok to treat them as the same. (Of course, I do expect that "having no contradictions" means having no contradictions *relative to the logic*. In normal propositional logic, absence any other axioms, the formulas "red all over" and "blue all over" are not contradictory. Sellars called these "material contradictions".) > My other problem is relating statements in an RDF database to > predicate logic. Again different people have subtly different ways of > doing this mapping. But, fortunately, we do have a standard: http://www.w3.org/TR/rdf-mt/ > The standard meaning of "interpretation" And it even discusses this: http://www.w3.org/TR/rdf-mt/#interp [snip] I suggest you start there. Cheers, Bijan.
Received on Thursday, 7 April 2005 01:45:48 UTC