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Re: inverse of a symmetric property?

From: Aldo Gangemi <aldo.gangemi@cnr.it>
Date: Tue, 29 Jun 2010 14:29:40 +0200
Cc: Aldo Gangemi <aldo.gangemi@cnr.it>, nathan@webr3.org, public-owl-dev@w3.org
Message-Id: <6FEA29FB-F570-48E5-972D-CF45F64ACAE3@cnr.it>
To: Uli Sattler <sattler@cs.man.ac.uk>
Nothing can say that they are identical, but we can infer that they are equivalent properties. Anyway, I checked that now with HermiT 1.2.4, FaCT 1.4, and Pellet 2.1:

source axioms (in OWL2 functional syntax):

Declaration(ObjectProperty(P))
SymmetricObjectProperty(P)
Declaration(ObjectProperty(InvP))
InverseObjectProperties(InvP P)

inferred axioms (the trivial ones are deleted):

InverseObjectProperties(P P)
InverseObjectProperties(P InvP)
SymmetricObjectProperty(InvP)
InverseObjectProperties(InvP InvP)
EquivalentObjectProperties(P InvP)

From the design perspective Uli is right: it's not trivial to find a use case that needs creating alternative names for inverse symmetric properties, because you get exactly the same result as when you create an equivalent property directly.

Best
Aldo


On 29 Jun 2010, at 12:08, Uli Sattler wrote:

> 
> Hi Nathan, I guess you mean the following, and an example of P would be "IsMarriedTo", which is symmetric, and you could even think of InvP as "hasSpouse"...in general, if a property is symmetric, you can't distinguish between that property and its inverse, so introducing a name for the inverse (rather than, say, an alternative name for the property itself) can be confusing...
> 
> Anyway, in the example below, there is nothing that would allow us to deduce that a and b are identical (in the same way as Mr and Mrs Miller aren't identical)...
> 
> But perhaps I completely misunderstood your question?
> 
> Cheers, Uli
> 
> ----
> 
> ObjectProperty: P
> 
>    Characteristics:
>        Symmetric
> 
>    InverseOf:
>        InvP
> 
> 
> ObjectProperty: InvP
> 
>    SubPropertyOf:
>        owl:topObjectProperty
> 
>    InverseOf:
>        P
> 
> Individual: b
> 
> Individual: a
> 
>    Facts:
>        P  b
> 
> 
> 
> On 29 Jun 2010, at 00:42, Aldo Gangemi wrote:
> 
>> it entails { :x owl:equivalentProperty :y }
>> 
>> aldo
>> 
>> On 29 Jun 2010, at 00:37, Nathan wrote:
>> 
>>> is { :x a owl:SymmetricProperty . :y owl:inverseOf :x } invalid or does it entail { :x owl:sameAs :y } ?
>>> 
>>> Best,
>>> 
>>> Nathan
>>> 
>>> ps: didn't know I could be that concise!
>>> 
>> 
>> 
>> 
>> _____________________________________
>> 
>> Aldo Gangemi
>> Senior Researcher
>> Semantic Technology Lab (STLab)
>> Institute for Cognitive Science and Technology,
>> National Research Council (ISTC-CNR)
>> Via Nomentana 56, 00161, Roma, Italy
>> Tel: +390644161535
>> Fax: +390644161513
>> aldo.gangemi@cnr.it
>> http://www.stlab.istc.cnr.it
>> http://www.istc.cnr.it/createhtml.php?nbr=71
>> skype aldogangemi
>> 
>> 
> 
> 



_____________________________________

Aldo Gangemi
Senior Researcher
Semantic Technology Lab (STLab)
Institute for Cognitive Science and Technology,
National Research Council (ISTC-CNR) 
Via Nomentana 56, 00161, Roma, Italy 
Tel: +390644161535
Fax: +390644161513
aldo.gangemi@cnr.it
http://www.stlab.istc.cnr.it
http://www.istc.cnr.it/createhtml.php?nbr=71
skype aldogangemi
Received on Tuesday, 29 June 2010 12:30:16 GMT

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