RE: Using cardinality restrictions

Hi Uli, hi @all,

 

Yes, that makes sense!

I was trying to build a small example analog to the famous pizza example.

The difference is that I do not want to assign instances to the partitions
and use them, but I want to just define instances and have the reasoner
interfere to which class they belong to.

I’m sorry … but I couldn’t achieve this yet. This is what I did:

My Class Hierarchy:

Thing

- RefClass

- TestValuePartition == (Part1 union Part2)

                - Part1

                - Part2

Part1 and Part 2 are marked as disjoint.

Furthermore, I defined that Part 1 has some references to RefClass (hasRef
some Class). 

Now, if I create two instances with asserted type TestValuePartition, one
that has a reference to an instance of RefClass and the other having no
instance.

Due to the value partition I would have expected that instance 1 is
interfered to be of Part1 and instance 2 to be of Part2, but again only
Part1 works!

Instance 2 stays as being a TestValuePartition instance (only). For me the
Value Partition is in this case not a value partition!? 

What am I missing?

 

Thanks a lot!

 

Cheers,

Sören

 

 

 

From: Uli Sattler [mailto:sattler@cs.man.ac.uk] 
Sent: Dienstag, 12. Juli 2011 17:35
To: Kemmann, Soeren
Cc: public-owl-dev@w3.org
Subject: Re: Using cardinality restrictions

 

 

On 12 Jul 2011, at 10:27, <Soeren.Kemmann@iese.fraunhofer.de> wrote:





Hi there,

 

I’m trying to model (with Protégé 3.4.6 with Pellet Reasoner … just in case
it matters) that a class A has two subclasses B and C, where B and C are
disjoint.

The distinction I want to make is that every instance of A is either of
subclass B or of C dependent on the cardinality of a property p.

The “test” is whether the instance has values assigned to property p ( p min
1). This kind of works … the instances are interfered to be of that type.

But the other class does not work. If tried (p max 0), (p exactly 0), (p
exactly 0 RangeClass), but nothing works.

 

I’m using OWL-DL and as far as I understood 0/1 cardinalities are ok for
OWL-DL, right?

 

 

Hi Soeren, 

 

yes, they do - I guess you have, in your ontology, something like 

 

B SubClassOf C   

A SubClassOf C  %% these two axioms aren't really necessary if you have the
2 below...

 

A EquivalentClass C and (p min 1) 

B EquivalentClass C and (p max 0) 

 

...and then when you have an instance of C with 

 

- 1 known p-successor, they are classified as being an instance of A

- no known p-successor, they are ... only classified as being an instance of
C - and you wonder why...

 

The reason is found in the word 'known' used above: your instance of C has
no *known* p-successor, but could have some, due to the open world
assumption!

 

So, how to rescue this? For example, you could say explicitly how many
p-successors an individual has...in general, you need a 'closure' statement
that says that the *known* p-successors are all p-successors. 

 

If I remember correctly, the famous Pizza tutorial explains this in detail
(see http://owl.cs.manchester.ac.uk/tutorials/protegeowltutorial/ )

 

Cheers, Uli





Thanks a lot!

Cheers,

Sören

 

 

Dipl. Inf. Soeren Kemmann
Fraunhofer IESE
Fraunhofer-Platz 1, 67663 Kaiserslautern, Germany
Tel.: +49 (0) 631 / 6800 - 2218
Fax.: +49 (0) 631 / 6800 - 9 2218
 <mailto:soeren.kemmann@iese.fraunhofer.de>
mailto:soeren.kemmann@iese.fraunhofer.de