RE: What is the Vocabulary of an Intersected Policy

Isn't this because of the negation issues?  The fact that C wasn't
selected is a different fact than C isn't in the vocabulary.
 
Cheers,
Dave


________________________________

	From: public-ws-policy-request@w3.org
[mailto:public-ws-policy-request@w3.org] On Behalf Of Sergey Beryozkin
	Sent: Thursday, April 19, 2007 6:01 AM
	To: Ashok Malhotra; ws policy
	Subject: Re: What is the Vocabulary of an Intersected Policy
	
	
	Hi
	 
	But the effective policy contains just A&B, this policy is the
output from the intersection, right ? At the intersection stage C & D
have already been discarded
	I don't understand why having C&D in the vocabulary of the
effective policy will help to avoid applying them. 
	 
	Cheers, Sergey

		----- Original Message ----- 
		From: Ashok Malhotra <mailto:ashok.malhotra@oracle.com>

		To: Sergey Beryozkin <mailto:sergey.beryozkin@iona.com>
; ws policy <mailto:public-ws-policy@w3.org>  
		Sent: Thursday, April 19, 2007 1:30 PM
		Subject: RE: What is the Vocabulary of an Intersected
Policy


		Sergey, you said ...

		> I don't understand. Why would the consumer need to
keep C&D in the vocabulary of the effective(calculated through the
intersection) policy if they can't be applied ?

		 

		Just to make sure C and D are not applied.

		All the best, Ashok 

		
________________________________


		From: public-ws-policy-request@w3.org
[mailto:public-ws-policy-request@w3.org] On Behalf Of Sergey Beryozkin
		Sent: Thursday, April 19, 2007 1:25 AM
		To: Ashok Malhotra; ws policy
		Subject: Re: What is the Vocabulary of an Intersected
Policy

		 

		Hi

		 

		My understanding is that A&B is the vocabulary of the
final effective policy, the fact that this policy was computed through
the intersection is not important

		 

		"BUT, Chris points out the vocabulary should be
{A,B,C,D} to remember the fact that this was the union of the
vocabularies of the two intersected policies and that {C. D} must not be
applied since they were not selected."

		 

		I don't understand. Why would the consumer need to keep
C&D in the vocabulary of the effective(calculated through the
intersection) policy if they can't be appplied ?

		 

		Cheers, Sergey

			----- Original Message ----- 

			From: Ashok Malhotra
<mailto:ashok.malhotra@oracle.com>  

			To: ws policy <mailto:public-ws-policy@w3.org>  

			Sent: Wednesday, April 18, 2007 10:19 PM

			Subject: What is the Vocabulary of an
Intersected Policy

			 

			We spoke briefly about this on the call today
and I see a problem.

			This note is an attempt to state the problem
clearly.

			Consider two normalized policies:

			<Policy>

			    <ExactlyOne>

			        <All>

			              <A/>

			               <B/>

			        </All>

			         <All>\

			                <C/>

			         </All>

			      </ExactlyOne>

			</Policy>

			<Policy>

			    <ExactlyOne>

			        <All>

			              <A/>

			               <B/>

			        </All>

			         <All>\

			                <D/>

			         </All>

			      </ExactlyOne>

			</Policy>

			Let us intersect these two policies.  What we
get is:

			<Policy>

			    <ExactlyOne>

			        <All>

			              <A/>

			               <B/>

			        </All>

			    </ExactlyOne>

			</Policy>

			Now, what is the vocabulary of this policy?
Looking at this policy alone it should be { A, B}.

			BUT, Chris points out the vocabulary should be
{A,B,C,D} to remember the fact that this was the union of the
vocabularies of the two intersected policies and that {C. D} must not be
applied since they were not selected.

			This seems like a contradiction.   To remember
the negative decision we need to include assertions that are not in the
policy, in its vocabulary.

			SOLUTIONS:

			The only viable solution that I can see is to
drop the 'negation' semantic, namely, "When an assertion whose type is
part of the policy's vocabulary is not included in a policy alternative,
the policy alternative without the assertion type indicates that the
assertion will not be applied in the context of the attached policy
subject."   (Dale was arguing for this on other grounds as well)  Some
would object strongly to this.  A counter proposal would be to add an
explicit NOT operator.

			Unfortunately, these are radical suggestions but
I do not see any other way out.   

			All the best, Ashok