Preconditions /effects vs Preconditions/Postconditions

In DAML-S we have Preconditions and Effects(Conditions and Effect).

BPEL4WS does not have the notion of Preconditions and Postconditions( to 
the best of my knowledge). However the ws-chor group  have defined 
Precondition and Postcondition for the use cases in their requirement 
document.

I am wondering if the semantics of the "Conditions" for "Effects" as 
defined in DAML-S are different from "Post conditions" in ws-chor doc, 
as  what we are really interested in is the condition itself.  What 
would be lost (just for the sake of argument) if we were to discard the 
notion of "effect" and retain only the condition part of "Effect" i.e if 
I may call it,  "Post condition". I say this because I feel that in some 
way the effect part gets reflected in the output. Maybe "Effect" makes 
it more explicit. I guess even for service composition, what we are 
really interested in apart from input -output is the conditions that are 
captured in Preconditions and Effects. I guess what I am really trying 
to say is can we simplfy the notion of Conditional effects by 
attributing it as "post condition" without compromising anything that is 
not covered in any other property parameter.

Any comments / thoughts well appreciated

Thanks,

Monika

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Monika Solanki
Software Technology Research Laboratory(STRL)
De Montfort University
Hawthorn building, H00.18
The Gateway
Leicester LE1 9BH, UK

phone: +44 (0)116 250 6170 intern: 6170
email: monika@dmu.ac.uk
web: http://www.cse.dmu.ac.uk/~monika
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Received on Thursday, 11 September 2003 12:18:21 UTC