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Re: Why (IMO) you should vote Yes to Motion 14.02

Zitat von Dan Zuras Intervals <intervals08@xxxxxxxxxxxxxx>:

so I'm trying to sort out if these really conflict with the ideas
expressed (especially) by John and Dan.

First of all a note to the proposed wording. If I read it

correctly,

Motion 14 does not rule out mid-rad intervals. The only thing it

says


        That is correct.  However, it may put an undue burden on
        a mid-rad format that is trying to 'appear' to the user
        as an inf-sup format.  Perhaps more than is desired.


(leaving the title of 6.1 aside for the moment) is that the bounds

must

be retrieved exactly, but it doesn't specify the nature of the

level 2


        Correct, nothing is specified except by its behavior.

        And the only behavior specified is that the bounds
        shall be exactly retrieved & that containment shall
        be preserved on type conversions.

        That's all.


datum. Additionally it mentions multi-precision representation of
intervals by the triple (x_hat, delta_l, delta_u) to be

conforming.


        It mentions this in the informative note.  There is
        nothing more going on here than that it is the intention
        that such a format MAY BE made to conform &, as such,
        should not be excluded.


Therefor a mid-rad representation seems to be conforming to these


        Just so, with some caveats.
This may be nitpicking, but 6.1 doesn't say anything about the level 2 datum it describes as being represented. You might infer from the notation that this has to be an interval with bounds in F, but that's not explicit in the text, is it? Therefor my note that the text itself doesn't exclude mid-rad. The mention of the note about the triple representation was to underline that a present note includes the possibility that the bound is exactly represented by a sum of two FP numbers with no requirement---besides notation and the nature of the level 2 datum---that this sum is itself an FP number. But as already put this is nitpicking and we shouldn't use it to justify support of formats but cater the wording to our decision. 

Cheers,

  Christian