- From: <jos.deroo.jd@belgium.agfa.com>
- Date: Mon, 23 Jul 2001 22:34:36 +0100
- To: connolly@w3.org
- Cc: bwm@hplb.hpl.hp.com, w3c-rdfcore-wg@w3.org

[...] > > <s> <p> "string" . is true in I if and only if: > > > > s is a member of U, p is a member of P and string is a member of S > > (IN(s), IS(string)) is a member of IEXT(I(p)) > > Just 3 major things missing: > > 1. existentials: > > _:x <p> <o> is true in I iff > o is a member of U, p is a member of P, > and there is some thingy tx in I's set of thingies > so that (tx, IN(O)) is a member of IEXT(I(p)) > > The substitution (tx for _:x) is > said to satisfy the triple _:x <p> <o>. > > In general, a substitution has > any number of (thingy for _:name, thingy2 for _:name2, ...) > pairs. I agree and understand 'substitution' as being a mapping from variables to thingies and usually the identity mapping except for the given pairs. A substitution denotes bindings of the variables and instances of the thingies. A substitution is a unifier of two thingies if the instances of these thingies by the substitution are identical. All the rest is just a matter of computing those unifiers and applying some rules of inference. > 2. conjunctions > > a list of triples is satisfied by > some substitution if each of the triples > in it is satisfied by that substitution. do you mean an (ordered) list or a set? indeed 'some' substitution is OK (not a Most General Unifier or MGU) > 3. putting it all together > > A list of triples is true in I iff there's some > substitution that satisfies it. fine > > > Pat goes on to demonstrate a use of this base model theory to > > define the meaning of reification: > [...] > > Pat points out an issue with reification, and I have another, > > but I suggest we get the base model theory sorted out before we get > > into that. > > Yes, let's leave that for a rainy day... Well, we had lots of rain here, but that is of course not everywhere... -- Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/

Received on Monday, 23 July 2001 16:35:15 UTC