From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>

Date: Wed, 19 Jun 2002 18:21:20 -0400

To: connolly@w3.org

Cc: www-webont-wg@w3.org

Message-Id: <20020619182120R.pfps@research.bell-labs.com>

Date: Wed, 19 Jun 2002 18:21:20 -0400

To: connolly@w3.org

Cc: www-webont-wg@w3.org

Message-Id: <20020619182120R.pfps@research.bell-labs.com>

Good. A proposal. From: Dan Connolly <connolly@w3.org> Subject: layering (5.3,5.10): a first-order same-syntax model theory Date: 19 Jun 2002 16:26:58 -0500 [...] > Additionally, owl reserves the following vocabulary: [...] I have no idea what ``reserves the ... vocabulary'' could mean. [...] > onProperty/hasClass: > if <?r, ?p> is in IEXT(I(ont:onProperty)) > and <?r, ?a> is in IEXT(I(ont:hasClass)), > then the set > { ?o: for some ?s in ICEXT(?r), <?s, ?o> is in IEXT(?p) > and ?o is in ICEXT(?a) } > has at least one element. Completely wrong. Something like then ICEXT(?r) = { ?o : exists ?x in ICEXT(?a) st <?o,?x> in IEXT(?p) } is needed here. Similarly for other restrictions. [..] > imports: > none. imports doesn't constrain interpretations > (other than having the subproperty relationship > with rdfs:seeAlso). Don't think so. imports means that the OWL KB pointed to should be considered to be part of this KB. A treatment of imports would be something like if <?KB1,?KB2> in IEXT(owl:imports) then the models of ?KB1 are a subset of the models of ?KB2. No particularly standard-first-order, however. [...] > conversely, > > if <?a, ?b> is in IEXT(I(ont:intersectionOf1)) > and <?a, ?c> is in IEXT(I(ont:intersectionOf2)) > and ?x is in ICEXT(?a). > then ?x is in ICEXT(?b) and in ICEXT(?c) What if happens if there is another ont:intersectionOf1 link from ?a? [...] > oneOf1/oneOf2: > > if <?a, ?b> is in IEXT(I(ont:oneOf1)) > and <?a, ?c> is in IEXT(I(ont:oneOf2)) > then ?b is in ICEXT(?a) > and ICEXT(?c) is a subset of ICEXT(?a). > > conversely, > if <?a, ?b> is in IEXT(I(ont:oneOf1)) > and <?a, ?c> is in IEXT(I(ont:oneOf2)) > and ?x is in ICEXT(?a) > then either ?x = ?b or ?x is in ICEXT(?c). Hmm. How does a oneOf finish? Suppose we have IEXT(I(ont:oneOf1)) = { <x,a> } IEXT(I(ont:oneOf2)) = { } Then what is the class extension of x? Suppose we have IEXT(I(ont:oneOf1)) = { <x,a> } IEXT(I(ont:oneOf2)) = { <x,x> } Then what is the class extension of x? [...] And, of course, there are no comprehension constraints, so x rdf:type _:y . _:y one:intersectionOf1 a . _:y one:intersectionOf2 b . does not entail that x rdf:type _:z . _:z one:intersectionOf1 b . _:z one:intersectionOf2 a . So, in sum, lots of problems. peterReceived on Wednesday, 19 June 2002 18:21:29 GMT

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