From: Jeff Thompson <jeff@thefirst.org>

Date: Tue, 26 Aug 2008 08:50:45 -0700

Message-ID: <48B42655.6000705@thefirst.org>

To: public-owl-dev@w3.org

Date: Tue, 26 Aug 2008 08:50:45 -0700

Message-ID: <48B42655.6000705@thefirst.org>

To: public-owl-dev@w3.org

Uli Sattler wrote: >> In >> other words, suppose you have the OWL 2 axiom: >> >> ObjectProperty: childRelatedToBrother >> SubPropertyChain: hasParent o owl:TopObjectProperty o hasBrother >> >> would that be the same as this rule: >> hasParent(x, y) ^ hasBrother(w, z) -> childRelatedToBrother(x, z) >> >> In other words, the parent of x does not need to be the same as the brother of z. >> > > Now this example looks very strange indeed: could you explain to us what the idea behind it is? Cheers, Uli I'm trying to fill out the table of combinations of variables for rules which can be converted to axioms without variables. You already have: hasParent(x, y) ^ hasBrother(y, z) -> hasUncle(x, z) and hasPerformer(x, y) ^ loves(y, y) -> hasPrimadonna(x, y) How about this one: hasParent(x, y) ^ ownsCastle(y, z) -> hasRichParent(x, y) Notice that the consequent has (x, y), not (x, z) so that z is unbound. I think this can done by turning ownsCastle(y, z) into a class description for y like OwnsCastle(y) with a someValuesFrom restriction on ownsCastle Class: OwnsCastle SubClassOf: ownsCastle some owl:Thing Then the rule becomes one which can be converted to OWL: hasParent(x, y) ^ OwnsCastle(y) -> hasRichParent(x, y) You see what I'm getting at. In general, I'm interested in the way that "Rewriting Rules into SROIQ Axioms" turns rules with variables into axioms without variables. Is there other work which turns all the forms of rules into axioms without variables, even if they aren't tractable OWL axioms? - JeffReceived on Tuesday, 26 August 2008 15:51:25 UTC

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