W3C home > Mailing lists > Public > public-ws-policy@w3.org > May 2007

Re: Editorial issues

From: David Hull <dmh@tibco.com>
Date: Wed, 02 May 2007 11:55:44 -0400
Message-ID: <4638B480.3050806@tibco.com>
To: Asir Vedamuthu <asirveda@microsoft.com>
CC: "public-ws-policy@w3.org" <public-ws-policy@w3.org>
Asir Vedamuthu wrote:
>
> > Should the first sentence read " ... a policy /alternative/ with zero
> policy assertions"?
>
>  
>
> Yes, we think so too. We suggest that a CR issue be raised for this
> change.
>
Does that mean you'll raise it or you would like me to raise it?
>
>  
>
> >Conversely, it seems odd that <Policy/> should denote an
>
> >/alternative/ not a policy.  Intuitively, an empty <Policy/> seems
>
> >like it should denote either a policy with no alternatives,
>
> >or perhaps a policy with a single empty alternative.
>
>  
>
> <Policy/> is a policy with a single empty policy alternative. Why? The
> Policy operator is equivalent to the All operator. A collection of
> assertions in an All operator is equivalent to a policy alternative.
> In this specific case, it is an empty alternative. That is, a policy
> with a single empty policy alternative.
>
That's not a big surprise, but in that case <Policy/> is /not/
equivalent to <All/>.  One is a policy and the other is an alternative.
>
>  
>
> > However, this seems counter-intuitive in the context of intersection,
> and "all of the assertions in both alternatives"
>
>  
>
> It is neither set union nor set intersection. It literally means all
> of the assertions in both alternatives.
>
Read literally, the phrase is ambiguous.  It should be recast.

If I have an alternative [A B] and an alternative [B C], then "all of
the assertions in both alternatives" could mean:

    * [A, B, C].  A is in the first alternative.  B is in the first and
      the second.  C is in the second.  That's all of them.
    * [B] B is the only assertion in both alternatives.
    * [A, B, B, C].  A is in the first alternative.  B is in the first
      alternative.  B is in the second alternative.  C is in the second
      alternative.

Since the first is set union, the second is set intersection and you say
that the desired answer is neither, and we know that duplicates are
allowed, I would now guess the third answer is right.  But at this
point, this is just a guess.
>
>  
>
> We hope this helps.
>
>  
>
> Regards,
>
>  
>
> Asir S Vedamuthu
>
> Microsoft Corporation
>
>  
>
>  
>
> *From:* public-ws-policy-request@w3.org
> [mailto:public-ws-policy-request@w3.org] *On Behalf Of *David Hull
> *Sent:* Monday, April 30, 2007 10:42 PM
> *To:* public-ws-policy@w3.org
> *Subject:* Editorial issues
>
>  
>
> The rule for "Empty" states
>
> |<wsp:All />| expresses a policy with zero policy assertions. Note
> that since |wsp:Policy| is equivalent to |wsp:All|, |<wsp:Policy />|
> is therefore equivalent to |<wsp:All />|, i.e., a policy alternative
> with zero assertions.
>
> Elsewhere it says that <All/> represents alternatives, not policies,
> and there is certainly a distinction between an empty policy and an
> empty alternative.  Should the first sentence read " ... a policy
> /alternative/ with zero policy assertions"?
>
> Conversely, it seems odd that <Policy/> should denote an /alternative/
> not a policy.  Intuitively, an empty <Policy/> seems like it should
> denote either a policy with no alternatives, or perhaps a policy with
> a single empty alternative.
>
> ------------------------------------------------------------------------
>
>
> The section on intersection states
>
> If two alternatives are compatible, their intersection is an
> alternative containing all of the assertions in both alternatives.
>
> This sounds like set union to me (except that we're not necessarily
> talking about sets).  If I talk about "all the people in both the USA
> and Canada", I'm not talking about people on the border, I'm talking
> about the combined populations.  However, this seems counter-intuitive
> in the context of intersection, and "all of the assertions in both
> alternatives" could be parsed as meaning "all of the assertions which
> are both in one alternative and in the other", that is, the set
> intersection (except that we're not necessarily talking about sets).
>
> It would be good to clarify exactly what is meant.
>
Received on Wednesday, 2 May 2007 15:55:55 GMT

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