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Re: the precondition property in OWL-S 1.0

From: David Martin <martin@ai.sri.com>
Date: Fri, 07 Nov 2003 22:33:00 -0800
Message-ID: <3FAC8E1C.7070703@ai.sri.com>
To: Marta Sabou <marta@cs.vu.nl>
Cc: www-ws@w3.org, public-sws-ig@w3.org

[Note: this thread is moving to public-sws-ig.  After this message, 
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Marta Sabou wrote:

>  Monika, Drew,
>  I completely agree with the proposed solution. This should definitely be
> implemented in the next release.

I also agree, except note that there are 2 proposals "on the table":

I think Monika suggested this:

     Process - hasPrecondition - Precondition
where Precondition is a subclass of Condition

whereas Drew seems to be suggesting this:

     Process - hasPrecondition - Condition

(with no Precondition class anywhere).

That reminds me - we still have an open issue about the class of an 
effect (that is, the range of ceEffect).  Currently it's just "Thing", 
which isn't very satisfying. Do people feel that it's OK to have 
Condition for this range, or do we need something distinct?

- David

>  Cheers,
> Marta
> Drew McDermott wrote:
>>   [Monika Solanki, in re DAML-S spec]
>>   Currently in the 1.0 version of the process model, we have the following
>>     <owl:Class rdf:ID="Precondition" />
>>   - <owl:ObjectProperty rdf:ID="preCondition">
>>     <rdfs:domain rdf:resource="#Precondition" />
>>     <rdfs:range rdf:resource="#Condition" />
>>     </owl:ObjectProperty>
>>   Where, Condition is defined as,
>>   - <owl:Class rdf:ID="Condition">
>>     <rdfs:comment>This is a "place-holder" for now, which awaits further
>>   work from the DAML/OWL community. An instance of Condition is a logical
>>   formula that evaluates to true or false. Eventually we expect this to be
>>   defined elsewhere, as part of a OWL extension allowing for logical
>>   expressions.</rdfs:comment>
>>     </owl:Class>
>>   Somehow I am not able to grasp the utility of the property
>>   "preCondition".  Since in this model, we have IOPEs as Classes,
>>   therefore I believe all we need to do is make Precondition a subclass of
>>   Condition.
>>    <owl:Class rdf:ID="PreCondition">
>>     <rdfs:subClassOf rdf:resource="#Condition" />
>>     </owl:Class>
>>   The property preCondition, introduces redundancy as it is ranging over
>>   the class "Condition" anyways.
>>   Feedback appreciated in case I missed something.
>>You're right, as far as I can see.  The important property is
>>hasPrecondition, which connects a Condition to a
>>Process or Process step.  There is no reason for the class
>>Precondition to exist, let alone a property preCondition linking a
>>Precondition to a Condition (itself?).
>>                                             -- Drew McDermott
>>                                                Yale University CS Dept.
Received on Saturday, 8 November 2003 02:23:23 UTC

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