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Re: Motion 31: V04.4 Revision of proposed Level 1 text



On 2012-02-29 09:40:26 +0100, Ulrich Kulisch wrote:
> P1788 members:
> 
> I have some difficulties with Section 3.1 of Draft 04.4:
> 3.1. Frequently used notation and abbreviations.
> 
> In 3.1. of Draft 04.2 the set of closed and bounded real intervals is
> denoted by IR. Then it says: IF denotes the set of intervals of IR whose
> bounds are in F.
> 
> This seems to me in accordance with the interval literature. "Classical
> interval analysis" deals with IR, sometimes also written as I(R). Also
> denotations like IR^n , IR^nxn , or IC (C stands for the complex numbers)
> are used.
> 
> Do I understand it correctly that by Draft 04.4 in all these notations now
> the I has to be underlined? Why that?

overlined. IIRC, the goal was to make the difference with the
non-overlined version (bounded, nonempty intervals). But this
non-overlined version has disappeared. If it is no longer useful
(but one may need to wait for the complete standard), how about
simplifying the notations, as you suggest?

> Also:
> 3.1. of  Draft 04.2 says: \overline{IF} denotes the subset of \overline{IR}
> whose bounds are in F.
> By Draft 04.4 only the I is overlined? This looks strange to me. Can anybody
> give me an explanation? I may have misst something during the discussion?
> 
> The notations of Draft 04.2 seem much more natural to me.

There were some discussions, but IIRC, there was just an inconsistency
in Draft 04.1. I don't know/remember why this has changed since 04.2.

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Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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