From: Dan Connolly <connolly@w3.org>

Date: Mon, 23 Jul 2001 02:36:41 -0500

Message-ID: <3B5BD409.3E97F31F@w3.org>

To: Brian McBride <bwm@hplb.hpl.hp.com>

CC: rdf core <w3c-rdfcore-wg@w3.org>

Date: Mon, 23 Jul 2001 02:36:41 -0500

Message-ID: <3B5BD409.3E97F31F@w3.org>

To: Brian McBride <bwm@hplb.hpl.hp.com>

CC: rdf core <w3c-rdfcore-wg@w3.org>

Brian McBride wrote: [...] Looks good, mostly... > Here goes: > > Let U be the set of URI References (as defined by RDF 2396). I don't think you mean that relative URI references are in U. I think U is the set of absolute URI references; i.e. URIs with optional #fragment thingies. > //ignore lang and namespaces for now > Let S be the set of of UNICODE strings (UNICODE*) > > An interpretation I consists of: > > A set R of thingies > > A subset P of thingies which corresponds to Properties > > A mapping IN : U -> R > > A mapping IEXT : P -> R x R // R cross R > > A mapping IS : S -> R > > <s> <p> <o> . is true in I if and only if: > > s, o are members of U, p is a member of P > (IN(s), IN(o)) is a member of IEXT(I(P)) that last P should be little, no? IEXT(I(p)) > <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. 2. conjunctions a list of triples is satisfied by some substitution if each of the triples in it is satisfied by that substitution. 3. putting it all together A list of triples is true in I iff there's some substitution that satisfies it. > 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... Just one of Pat's notes seems essential: > (Literals are required by law > to map to a certain subset of thingies in a predefined way, but > otherwise are treated like any other names.) I'd say literals map to themselves. i.e. IS is the identity function. But that depends on my position on xml:lang... -- Dan Connolly, W3C http://www.w3.org/People/Connolly/Received on Monday, 23 July 2001 03:38:06 UTC

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