Re: The current proposal
On Wed, 25 Feb 2009 15:41:02 -0100, Arnold Neumaier
<Arnold.Neumaier@xxxxxxxxxxxx> wrote:
Always???
This value is not even properly defined in many cases,
such as when F(x)=x-x or F(x)=(x-1)/(x+1) and A=[0,inf].
This was spoken in terms of established practice in the
mathematical community at large. I find it extermely important
that we do not create sectarian deviations from very established
practices.
Yes.
We can change with the standard the practice of interval computation,
but not the practice of mathematics.
What about F(x)=(x^2-1)/(x-1) for x=1? There seem some choices to
implement this function following the Vienna proposal, but if I
understand it correctly, the result is always Empty.
Given this, does this change practice in mathematics?
In mathematics there are exactly two possibilities, either
the result F(1) is undefined or, after some obvious modification,
the result is F(1)=2. It is not the empty set.
Is it reasonable that a mathematically defined object, which
may be the result of legal operations such as intersection,
is used to indicate something else, is used as a flag?
Any opinions?
Cheers, Siegfried M. Rump
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Prof. Dr. Siegfried M. Rump
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Hamburg University of Technology
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and
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