[Crm-sig] subproperty - superproperty

[Stephen Stead]

My understanding is: yes there can be such an instance.
For instance An Actor can be present at a Measuring Event without actual
performing it.
Rgds
SdS



Stephen Stead

Tel +44 20 8668 3075 

Mob +44 7802 755 013

E-mail steads at paveprime.com


-----Original Message-----
From: crm-sig-bounces at ics.forth.gr [mailto:crm-sig-bounces at ics.forth.gr] On
Behalf Of Christian-Emil Ore
Sent: 11 June 2007 13:48
To: crm-sig
Subject: [Crm-sig] subproperty - superproperty

Dear all,
I may well be blind, but I cannot find the following specified in the 
crm-definition:

Assume we have four class (could be two) Ei, Ej, Ek, El and two 
properties Pa, Pb

Ek is a sub class of Ei
El is a sub class of Ej

Pa: Ei <-> Ej
Pb: Ek <-> El

which can be illustrated by the diagram

           Pa
   Ei   <---->   Ej
   |	  |	|
   |       |     |
   |       |     |
   Ek   <---->   El
           Pb

It is clear that each instance of a Pb will be a Pa when seen as a 
property on the superclass level. That is ordinary object orientedness 
and well documented in the crm standard.

Since Ek and El are subclasses of Ei and Ej, the properties between Ei 
and Ej, that is, Pa will also be a property between Ek and El. However, 
can there exist an instance of Pa:Ek <--> El that is not an instance of Pb?

Regards,
Christian-Emil
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