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Re: Some fuzzy with cardinality restriction vs complex property in OWL

From: Yuzhong Qu <yzqu@seu.edu.cn>
Date: Sat, 16 Oct 2004 15:19:55 +0800
Message-ID: <003c01c4b350$8a06e600$fd0b77ca@xobjects>
To: "Ivan Herman" <ivan@w3.org>
Cc: <www-rdf-interest@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
[Yuzhong Qu wrote:]
> The OWL S&AS says:
> To preserve decidability of reasoning in OWL Lite, not all properties 
> can have cardinality restrictions placed on them or be specified as 
> functional or inverse-functional. An individual-valued property is 
> complex if
> 1/ it is specified as being functional or inverse-functional,
> 2/ _there is some cardinality restriction that uses it,_
> 3/ it has an inverse that is complex, or
> 4/ it has a super-property that is complex.
> Complex properties cannot be specified as being transitive.
> It seems OK, but some mistiness arises when diving into the deeps.
> We know that:
> someValuesFrom(owl:Thing) is logically equivalent to minCardinality(1)
> and someValuesFrom(SomeNonEmptyClass) logically implies minCardinality(1)

[Ivan Herman wrote:]

I am not sure that is true. Isn't it correct that:

- someValuesFrom(owl:Thing) simply means that *if* there are values *then* at least one
myst be from owl:Thing, whereas minCardinality(1) means that there *must* be at least one

and the same for the second statement?

[Yuzhong Qu] No. someValuesFrom(owl:Thing) means that there must exist one which is from owl:Thing.

> My questions:
> 1. Suppose there is an existential restriction that uses a 
> property, should the property be considered as a complex property?
> It seems not. But how to explain the implication of the above axioms?
> 2. Is there any meaning with minCardinality(0)? does it make the 
> corresponding property become a complex property?
> e.g.
> restriction( myProperty minCardinality(0)) makes myProperty become a 
> complex property?
> Thanks for your concern!
> Yuzhong Qu 

Received on Saturday, 16 October 2004 07:20:38 UTC

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