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Re: RIF and QL

From: <jos.deroo@agfa.com>
Date: Fri, 27 Jan 2006 20:17:05 +0100
To: pfps@inf.unibz.it
Cc: public-rif-wg@w3.org
Message-ID: <OF4C136561.8EB7E899-ONC1257103.0068F466-C1257103.0069E359@agfa.com>

Peter F. Patel-Schneider wrote:
>> [...]
>>> Take, for example, the case in <http://www.w3.org/2005/rules/wg/wiki/ 
>>> Managing_incomplete_information#disjunctive-info>, which I rephrase 
>>> below.
>>>
>>> Given a KB with the only axiom:
>>>
>>>    kb:customer rdfs:subClassOf unionOf(kb:paysCash kb:paysCC).
>>>
>>> and the fact:
>>>
>>>    kb:customer("Paul").
>>>
>>> and the rules:
>>>
>>>    cons:paying-customer(X) :- kb:customer(X), kb:paysCC(X).
>>>    cons:paying-customer(X) :- kb:customer(X), kb:paysCash(X).
>>>
>>> we actually get, as expected, with either SWRL FOL semantics or 
>>> Rosati's style LP semantics:
>>>
>>>    cons:paying-customer("Paul").
>>>
>>> But with the local evaluation of each body I don't get it.
>> 
>> 
>> Well, maybe I'm sleeping, but when instead of your 2 rules (in N3)
>> {?X a kb:customer. ?X a kb:paysCC} => {?X a cons:paying-customer}.
>> {?X a kb:customer. ?X a kb:paysCash} => {?X a cons:paying-customer}.
>> 
>> I use a single rule
>> {?X a ?C. ?C owl:unionOf (kb:paysCash kb:paysCC)} => {?X a 
>> cons:paying-customer}.
>> 
>> then given the facts
>> kb:customer rdfs:subClassOf [ owl:unionOf (kb:paysCash kb:paysCC)].
>> :Paul a kb:customer.
>> 
>> and given the rules
>> http://www.agfa.com/w3c/euler/rpo-rules.n3
>> 
>> I'm getting proof evidence (*) for
>> :Paul a cons:paying-customer.
>> 
>> What am I missing??
>
> Well, perhaps, that you changed the rule, which is stepping outside
> of the permissable actions?

Really? :-)
I would have thought that

{?X a kb:customer.
 ?X a ?C.
 ?C owl:unionOf (kb:paysCash kb:paysCC)}
=>
{?X a cons:paying-customer}.

and

{?X a kb:customer.
 ?X a kb:paysCC}
=>
{?X a cons:paying-customer}.

{?X a kb:customer.
 ?X a kb:paysCash}
=>
{?X a cons:paying-customer}.

are equivalent rulesets, no?

-- 
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Friday, 27 January 2006 19:17:22 GMT

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