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DAML+OIL - subsumption and multiple constraints on the same property

From: Matt Halstead <matt.halstead@auckland.ac.nz>
Date: Thu, 15 May 2003 15:08:20 +1200
Message-ID: <3EC304A4.7030200@auckland.ac.nz>
To: www-rdf-logic@w3.org

I am beginning to confuse myself with direct subClass relationships in 
DAML+OIL.  The example follows :


Class A
     subClassOf
          hasObject    X  1*     ( means property hasObject  hasClass  X
                                   with cardinality 1 or more)


Class B
     subClassOf        A

     subClassOf
          hasObject    Y   1=

     subClassOf
          hasObject    Z    1*


Class X


Class Y
      subClassOf       X


Class Z
      subClassOf       X


What I am trying to do

Class A has a property hasObject that can be one or more objects of 
class X.  Now I want to make a more specialized form of Class A called 
Class B that is a subclass of A, but has the restrictions that it needs 
exactly one object of Class Y and at least 1 or more objects of Class Z. 
  Class Y and Z are more specialized forms of Class X.  If I take away 
the subClass of A restriction of Class B then I can still look at it and 
say members of Class B are certainly members of Class A.  But now I seem 
to have lost the explicit feeling that subClass of A gave, especially 
when using an editor such as OilEd.

The interpretation of multiple contraints on the same property

I need to understand if my thinking is correct.  The way I interpret 
Class B is as follows :

There are 3 anonymous classes that Class B is some function of.

1) the class of all individuals that have at least 1 or more hasObject 
properties of type X

2) the class of all individuals that have at exactly 1 property 
hasObject of type Y

3) the class of all individuals that have at least 1 or more hasObject 
properties of type Z

2) and 3) are subsets of 1)

We now form the conjunction of these restrictions, so that Class B is 
the class of individuals that have exactly one hasObject property of 
type Y and at least one or more hasObject properties of type Z, and that 
this forms a subset of the class of individuals that have 1 or more 
hasObject properties of type X.  The fact I have used subclass say that 
these are necessary, but not sufficient conditions for membership.


Is my interpretation is correct?

regards
Matt
Received on Wednesday, 14 May 2003 23:08:44 GMT

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