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Re: Motion 6



       John,

> As lots of people have said, there is nothing to stop a specialist  
> interval package (call it SIP), such as an arbitrary precision one,  
> using midrad for various algorithms. The arguments in favour are strong.

this applies to infsup too, no?

> Paul, I am still puzzled about what worries you. It seems to be  
> something to do with interoperability -- an "interchange format", as  
> has begun to be discussed.

assume P1788 would only standardize midrad, and infsup is better
for your favorite application. Wouldn't you be worried?

> Suppose SIP wants midrad as a private interchange format between its  
> own components. Fine, that is no concern of P1788.
> 
> Suppose SIP is going to be integrated into, say, the Maplematica  
> algebra package. So the latter can do improved arbitrary precision  
> interval computations, and display VERY narrow intervals as results.  
> Suppose you want midrad as an interchange format between SIP and  
> Maplematica, which seems appropriate for such a case. I would argue  
> that again, it is an issue between SIP and Maplematica.
> 
> It seems pure waste of time for P1788 to try standardise that  
> situation, because there are lots of details it doesn't know (which  
> may be commercial-in-confidence, and which would be different if SIP  
> were to interface to another package, say MuthPad).

again, all of the above applies to infsup too.

> Maybe, however, we could standardise a midrad form in the input/ 
> output section of P1788? For instance, as decimal text strings  
> indicating m +- r where m and r are number strings of arbitrary (not  
> necessarily the same) length. Arnold Neumaier already has something  
> proposed on these lines, I think.

I just wanted to remind the P1788 working group that there are other
applications of interval arithmetic outside 53-bit precision...

Paul Zimmermann