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Subject: Re: [xacml-comment] Public Comment

• From: Polar Humenn <polar@syr.edu>
• To: Haruyuki Kawabe <Haruyuki.Kawabe@unisys.co.jp>
• Date: Fri, 29 Oct 2004 10:40:31 -0400 (EDT)

```
Thank you Haruyki-san. After some invesigation, I believe you led me to
some errors in the notation of the new document. I will comment on

On Fri, 29 Oct 2004, Haruyuki Kawabe wrote:

> It means that the result of all-of operation is True if its third
> argument is  an empty bag,  right ?
> It is formally consistent but  a strange result intuitively.

Well, that all depends on if your an ordinal thinker (0) or a cardinal
thinker (1). :^)

I once had a philosphy professor who taught a "Philosophy of Mathematics"
course, and the conclusion of this course was that "the empty set didn't
exist".

But then, again, really, neither did the chair I was sitting on. :^)

> (And the result of all-of-any and all-of-all  is True if their second
> argument is an empty bag.)

Your are correct for "all-of-all". However, for "all_of_any", it's a bit
more complex.

all_of_any f []     [] = True

(This result is contrary to what is in the spec, which is one of the
errors. See below).

However, if the first list is not empty:

all_of_any f (x:xs) [] =
any_of f x []  &&  all_of_any f xs []

which reduces to:
False && all_of_any f xs []

which reduces to

False

However, you have pointed out an error in the specification as the first
clause of "all_of_any" (line 4651) is wrong and should read:

all_of_any f [] ys = True

not "False".

Cheers and Thanks!!!
-Polar

> Haruyuki Kawabe
> Haruyuki.Kawabe@unisys.co.jp
>
> >
> >Cheers,
> >-Polar
> >
> >On Thu, 28 Oct 2004 comment-form@oasis-open.org wrote:
> >
> >
> >
> >>Comment from: Haruyuki.Kawabe@unisys.co.jp
> >>
> >> In a XACML 2.0 core specification access_control-xacml-2_0-core-spec-cd-02.pdf,
> >>there is a Haskell notation specifying the semantics of the all-of higer order function (line 4572 - 4574).
> >>It seem to me that the result of the operation  is always False since the last clause (line 4574) use logical "AND" and the value of the terminal expression is False (line 4573).
> >>So the line 4573 should be
> >>    all_of f a [] = "True"
> >>
> >>Similar change would be required for all-of-any (line 4651) and all-of-all (line 4733).
> >>
> >>
> >>
>
```

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