Dear all,
I have now got the explanations and examples I needed, thanks: There can
be instances of the super property and the sub property in the example
below.
I asked because in many object oriented programming languages this will
not be allowed. On the subclass level the sub property will hide the
super property. This is apparently also the case in Telos which is the
underlying formalism for CRM.
It is easier not to assume/use such a hiding mechanism. A strict hiding
mechanism would have required a lot of "dummy" sub properties.
The sub property/sub class mechanism need perhaps a somewhat more
elaborated description/definition in the introduction?
Regards,
Christian-Emil
On 12.06.2007 17:43, Stephen Stead wrote:
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 [email protected]
-----Original Message-----
From: [email protected] [mailto:[email protected]] 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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