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Re: FW: [Bug 4553] Exact meaning of "all of the assertions in both alternatives"

From: David Hull <dmh@tibco.com>
Date: Tue, 22 May 2007 18:02:21 -0400
Message-ID: <4653686D.8060805@tibco.com>
To: Christopher B Ferris <chrisfer@us.ibm.com>
CC: Asir Vedamuthu <asirveda@microsoft.com>, "public-ws-policy@w3.org" <public-ws-policy@w3.org>, public-ws-policy-request@w3.org
That text seems fine to me.

BTW, it seems like the formatting is getting munged at some point in
including my message in the reply.

The archived version of what I sent is fine
(http://lists.w3.org/Archives/Public/public-ws-policy/2007May/0179.html). 
My original text ("* Bag union ...") has two >s in front of it, Asir's
reply ("Your first interpretation ...") has one > and my reply to him
("This is where ...") has none.  But in the version included in the
message I'm replying to now, all three have one > in front of them,
making it very hard to tell who's saying what.  This is also true in the
archive (that is, the archive of the message I'm replying to also has
the quoting flattened out).

Christopher B Ferris wrote:
>
> How about:
>
> If two alternatives are compatible, their intersection is an
> alternative containing
> all of the occurrances of all of the assertions in both alternatives
> (i.e., the bag
> union of the two).
>
> Cheers,
>
> Christopher Ferris
> STSM, Software Group Standards Strategy
> email: chrisfer@us.ibm.com
> blog: http://www.ibm.com/developerworks/blogs/page/chrisferris
> phone: +1 508 377 9295
>
> public-ws-policy-request@w3.org wrote on 05/15/2007 11:35:11 PM:
>
> > Asir Vedamuthu wrote:
> > * Bag union: [A B B B C C C C C D D] (all
> > occurrences of all assertions from 1
> > together with all occurrences of all assertions from 2)
> >    
> >
> > Your first interpretation is correct!
> >
> > The phrase "all of the assertions" is neither set union nor set
> > intersection. It literally means all of the assertions in both
> alternatives.
> >
> > If you think the phrase "all of the assertions" does not capture the
> > intent, may I request you to propose a concrete wording?
> >  
> > This is where one gets into trouble using lesser-known structures
> > like bags.  It would be nice to say
> >
> > "If two alternatives are compatible, their intersection is the bag
> > union of the two alternatives."
> >
> > Unfortunately, "bag union" is not a widely-recognized term.  Another
> > attempt would be to refer to policy expressions, since just
> > concatenating the contents of two (normalized) <All> expressions
> > will produce an expression for the bag union (which, I suspect, is
> > why "all of the assertions in both alternatives" may seem obvious).
> > Unfortunately, we're defining an operation on policies, not policy
> > expressions.  I suppose you could say
> >
> > "If two alternatives are compatible, their intersection may be
> > represented by a policy expression formed by concatenating their
> > normalized expressions."
> >
> > It's a mouthful, but it probably comes closest to capturing the
> > intuition behind the original statement.  Failing that, you could
> > bite the bullet and spell out bag union here:
> >
> > "If two alternatives are compatible, their intersection is an
> > alternative in which the multiplicity of each assertion is the sum
> > of the multiplicities in the two alternatives."
> >
> > or something equally unwieldy.
> >
> > Finally, if you prefer to keep the original wording, at least gloss it:
> >
> > "If two alternatives are compatible, their intersection is an
> > alternative containing all of the assertions in both alternatives
> > (i.e., the bag union of the two)."
> >
> > That's probably close enough.  It also reinforces that you don't
> > mean just any alternative containing all of the assertions in both
> > alternatives, but one containing only those assertions.
> >
> > Regards,
> >
> > Asir S Vedamuthu
> > Microsoft Corporation
> >
> >
> > -----Original Message-----
> > From: public-ws-policy-qa-request@w3.org [mailto:public-ws-policy-
> > qa-request@w3.org] On Behalf Of bugzilla@wiggum.w3.org
> > Sent: Friday, May 11, 2007 8:31 AM
> > To: public-ws-policy-qa@w3.org
> > Subject: [Bug 4553] Exact meaning of "all of the assertions in both
> > alternatives"
> >
> >
> > http://www.w3.org/Bugs/Public/show_bug.cgi?id=4553
> >
> >            Summary: Exact meaning of "all of the assertions in both
> >                     alternatives"
> >            Product: WS-Policy
> >            Version: CR
> >           Platform: All
> >                URL: http://lists.w3.org/Archives/Public/public-ws-
> >                     policy/2007May/0019.html
> >         OS/Version: All
> >             Status: NEW
> >           Severity: normal
> >           Priority: P2
> >          Component: Framework
> >         AssignedTo: fsasaki@w3.org
> >         ReportedBy: dmh@tibco.com
> >          QAContact: public-ws-policy-qa@w3.org
> >
> >
> > It is not clear which of three operations is meant in the statement
> > (in section
> > 4.5) that "If two alternatives are compatible, their intersection is an
> > alternative containing all of the assertions in both alternatives".
> I can see
> > four significantly different possible interpretations of this.  Suppose
> > alternative 1 consists of [A B B C C C] and alternative 2 consists
> of [B C C D
> > D].  Then the "intersection" of these could be
> >
> > * Bag union: [A B B B C C C C C D D] (all occurrences of all
> assertions from 1
> > together with all occurrences of all assertions from 2)
> > * Bag intersection: [B C C] (A is not in both, B occurs (at least)
> once in
> > both, C occurs (at least) twice in both, D is not in both)
> > * Set union: {A B C D} (all assertions from 1 together with all
> > assertions from
> > 2)
> > * Set intersection: {B C} (all assertions occurring in both 1 and 2).
> >
> > Though set intersection and set union seem to match the text most
> closely, it
> > seems unlikely that this is what is meant, given that alternatives
> > are bags and
> > multiplicity is in some way significant.
> >
> > The spec should say explicitly which operation is meant.
> >
> >   
Received on Tuesday, 22 May 2007 22:02:49 UTC

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