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Re: position paper on comparisons



On 2010-04-17 12:59:51 +0100, John Pryce wrote:
> A.
> Despite my previous posting about this, and trying hard to answer it
> for myself, I have no answer to the question:
>    What practical use has the Kulisch comparison xx <= yy,
>    meaning (xx.inf <= yy.inf and xx.sup <= yy.sup) ?

I had to use the following relation in the past (1995), though
this was in manual proofs rather than interval arithmetic:

xx <= yy defined as

    for all y in yy, there exists x in xx such that x <= y
  and
    for all x in xx, there exists y in yy such that x <= y

Here, I think this is equivalent to Kulisch comparison.

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