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Re: Motion P1788/M0037.01:MidAndRadSpecs: provisional NO



Does anyone have a strong opinion on whether mid(Empty) = NaN or mid(Empty) = -\infty? or something else?

Baker

On 10/21/2012 03:30 AM, John Pryce wrote:
P1788

I vote NO, on the grounds that mid and rad of Empty were omitted from the motion, see my recent queries appended. I will change my vote to YES as soon as this is satisfactorily clarified.

Chair: This doesn't change what the motion currently specifies, but only adds to it, so I hope we can just carry on voting after this clarification.

IMHO the only sensible value for mid(Empty) is NaN. Any real value falsifies the Level 2 invariant mid(xx) \in xx, which holds in all other cases. For rad(Empty), I'm easy between -oo and NaN with a small preference for -oo, on the grounds that I also slightly prefer wid(Empty) to be -oo.

John Pryce

On 20 Oct 2012, at 23:30, Ralph Baker Kearfott wrote:
The voting period herewith
begins.  Voting will continue until after Saturday, November 10, 2012.
Voting on this motion will proceed according to the rules for
position papers (quorum and simple majority).
Comment can continue during voting, but the motion
cannot be changed during voting.

On 19 Oct 2012, at 15:48, John Pryce wrote:
What do you want midpoint(Empty) to be? Not also 0 by natural symmetry, I hope?

On 19 Oct 2012, at 18:06, John Pryce wrote:
... IMO the correct recipe is
   wid(xx) returns the smallest F-number ≥ the mathematical width xhi-xlo.

Vladik: what is the Level 2 width of Empty? I would be happy with

  NaN, on the grounds that it is genuinely undefined;
or
  -oo, on the grounds that wid(xx) = (sup xx) - (inf xx), and when
       xx=Empty, one has sup xx = -oo and inf xx = +oo.




--

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Ralph Baker Kearfott,   rbk@xxxxxxxxxxxxx   (337) 482-5346 (fax)
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Department of Mathematics, University of Louisiana at Lafayette
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