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[protege-owl] re asener that support constraints

bassiee back_to_basic_69 at hotmail.com
Tue May 13 20:54:10 PDT 2008


Hey,
I think that I understand what you are trying to say...but still a few
questions.
Is there a way to write an DL-safe constraint for the example?
Is the rule below SWRL correct but not DL-safe?:
>So it looks to me a SWRL constraint with an empty head:
>Class1(?x) and Class1(?y) and sameAs(?x,?y) and hasClass2a(?x,?z) and
>hasClass2b(?y,?a)and sameAs(?z,?a) -->
Regards seba

Martin O'Connor wrote:
> 
> 
> It is actually more complex than I indicated in an earlier response. 
> Using a standard first order interpretation, a SWRL rule with an empty 
> head is basically stating that its antecedent is false - in your example 
> that would imply that ?z and?a cannot be the same. However, using a 
> DL-safe interpretation [1] the rule will be interpreted differently - 
> because DL-safe rules only bind to known individuals the rule will only 
> fire if it finds a ?z and ?a that are the same (assuming all other atoms 
> in the rule are true also). So it acts like a constraint in the latter 
> case. All SWRL reasoners that I am aware of use the DL-safe
> interpretation.
> 
> Martin
> 
> [1] http://protege.cim3.net/cgi-bin/wiki.pl?SWRLLanguageFAQ#nid9VC
> 
> bassiee wrote:
> 
>>Are you sure?
>>Martin told me that if a construction is build with an empty head, then it
>>can't occur.
>>So 'Woman(Paul)-> ' Means that Paul can't be a woman.
>>So: 2 Classes: Class1 and Class2
>>2 properties: hasClass2a and hasClass2b both have domain Class1 and range
>>Class2
>>'individual1' of Class1 has a property 'hasClass2a' to 'individual2' of
>>Class2
>>'individual1' of Class1 has a property 'hasClass2b' to 'individual3' of
>>Class2
>>and individual2 and individual2 have to be different.
>>
>>So it looks to me a SWRL constraint with an empty head:
>>Class1(?x) and Class1(?y) and sameAs(?x,?y) and hasClass2a(?x,?z) and
>>hasClass2b(?y,?a)and sameAs(?z,?a) -->
>>
>>So this means that (?z,?a)  can't be the same, so have to be different...
>>Could somebody confirm that please?
>>Thanks seba
>>
>>
>>
>>Samson Tu wrote:
>>  
>>
>>>I think you want to have
>>>
>>>Class1(?x) and Class1(?y) and sameAs(?x,?y) and hasClass2a(?x,?z) and
>>>hasClass2b(?y,?a) and differentFrom(?z,?a) -->
>>>
>>>not sameAs(?z, ?a).
>>>
>>>
>>>Samson
>>>
>>>
>>>bassiee wrote:
>>>
>>>    
>>>
>>>>>bassiee wrote:
>>>>>        
>>>>>
>>>>>>hey martin,
>>>>>>if you say that the jess back end in the swrltab supports a constraint
>>>>>>with
>>>>>>an empty head
>>>>>>then I probably don't understand how constraints have to be
>>>>>>interpreted.
>>>>>>So I give an example and if you could say it is correct or not (and
>>>>>>what
>>>>>>I
>>>>>>should be) that would be great.
>>>>>>
>>>>>>The example is very similar to what I want:
>>>>>>2 Classes: Class1 and Class2
>>>>>>2 properties: hasClass2a and hasClass2b both have domain Class1 and
>>>>>>range
>>>>>>Class2
>>>>>>I want to say in the constraint: an individual of Class1 can have a
>>>>>>connection to Class2 via 'hasClass2a' and 'hasClass2b', but the
>>>>>>individuals
>>>>>>it connects to have to be different.
>>>>>>
>>>>>>So it looks to me a SWRL constraint with an empty head:
>>>>>>Class1(?x) and Class1(?y) and sameAs(?x,?y) and hasClass2a(?x,?z) and
>>>>>>hasClass2b(?y,?a)
>>>>>>and sameAs(?z,?a) -->
>>>>>>
>>>>>>Is this correct?
>>>>>>          
>>>>>>
>>
>>  
>>
> 
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