# Re: Planning under Description Logic ?--an obstacle towards WSAC

From: Manshan Lin <lmshill@gmail.com>
Date: Fri, 10 Dec 2004 16:41:01 +0800
Message-ID: <ced14a84041210004162a9e609@mail.gmail.com>

Cc: Juergen Zimmer <jzimmer@inf.ed.ac.uk>
```
> Basically, inference-rules are like operators except that they don't
> occur in the final plan.

I suddently find that there is a problem when treating inference-rules
as operators. If we teat them as operators, they are such special
operators with the following characteristics:
(1) As you mention, they don't occur in the final plan
(2) They must be "executed" whenever their can be apply. It is
not like other operators, which will never be excuted if you don't

This will add unexpected complexity in planning algorithm.
Considerting the following situation (sorry for not being able to
provide a pratical example):
(1) inference rule: x:ClassA and x:ClassB -> x:Complementof(ClassC)
(2)
action-1:
Precondition: x:ClassC
Effect: x:ClassA
action-2:
Precondition: x:ClassC
Effect: x:ClassB
action-3:
Precondition: x:ClassC and x:ClassA
Effect: x:ClassD
(3)
initial: a: ClassC
goal: a:ClassB and a:ClassD

If we don't consider the characteristic (2), the generated plan would
probably be: action-1, action-2, action-3, while the proper plan
should be action-1, action-3, action-2. How to take these inference
rules into consideration when planning is really a problem.

--
Best regards!

Manshan Lin (林满山)
Email: lmshill@hotmail.com;lmshill@gmail.com
Affiliation: School of Computer Science and Engineering, the South
China University of Technology
Phone: (+86)13711287277
2004-12-10
```
Received on Friday, 10 December 2004 08:41:32 UTC

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