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[protege-owl] Protege OWL and restrictions
tar at ISI.EDU
Mon Apr 19 10:59:31 PDT 2010
On Apr 18, 2010, at 4:46 PM, Mariusz Chmielewski wrote:
> I have been testing several constructions In my ontology to achieve
> simple situation
> 1. I have defined 3 Enumeration Classes A1 A2 A3 (each of them
> with set o f3 individuals I1A1,I2A1,I3A1…. And so on)
> 2. I have defined a class C1
> 3. Property C1-A1 C1-A2 C1-A3
> 4. Then I define two subclasses C1_1 C1_2 of C1 which consist
> of value restrictions
> a. AllValuesFrom restriction
> b. With two optional restriction - exactly 1 (for mendatory
> value) or max 1 (for optional value)
> When I create the individual protégé shows proper form for defining
> individuals (red border for exactly 1 – no border for max 1) for
> properties but when I add SomeValesFrom all the form elements have
> red border.
Well SomeValuesFrom includes a Minimum Cardinality 1 restriction, so
at least one value of the given type is required. That would explain
why there is a red box.
> What is the idea for properly defining optional and mandatory
> properties to fill while defining class restrictions?
Well, I think that minimum 1 and no minimum value is what you want to
use for mandatory and optional values. Note that because of open
world, individuals with "mandatory" values don't actually need to have
any particular value specified.
Also, the red box GUI item is a hold-over from the Frame
representation of Protege and doesn't always work exactly the way you
might wish when working with OWL ontologies. In that sense, it is
probably better not to rely on it.
I would also point out that open world reasoning makes maximum and
exact cardinalities a bit problematic for reasoning. Especially when
you have an exactly 1 restriction, it may make more sense to make sure
that the Property in question is a FunctionalProperty.
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