Re: A proposal for motion 5 "Arithmetic operations for intervals"
Bo, Ulrich, P1788 members
On 3 Jun 2009, at 10:54, Ulrich Kulisch wrote:
Nevertheless, we are grateful for all arguments. The proposal will
be rearranged. Other duties do not allow
to do this in the three weeks timeframe. So we withdraw the motion
for the moment.
I have read your text more carefully (BTW can it please be submitted
as an official position paper so it has a serial number PPnnn to
refer to it by?). I had not realised, what Juergen pointed out to me,
that the formulae (RG) and the following unlabeled one, on p4, are
actually what I think of as the _definitions_ of operations. Hence
these comments:
1. The op-tables on pp 1-3 are suggestions for _implementation_.
Juergen's thought was that they should be included in the level 3
part of the standard.
2. Can you put the p4 stuff at the start of the document? As Juergen
pointed out, the Basic Theorem of Interval Arithmetic can be proved
from these p4 definitions.
3. I suggest in the unlabeled eqn on p4, you replace
aa ◦ bb := { a ◦ b | a in aa and b in bb }
by
aa ◦ bb := { a ◦ b | a in aa and b in bb and a o b is
defined }
to make it quite clear that out-of-domain points are just ignored
in this definition.
4. Then, your current p4 stuff is more or less saying the same thing
as the definitions in my (under revision) multi-format motion, except
you only mention the 4 basic ops, and I cover general multivariate
point-functions, which _are_ necessary. So it would be nice for us to
converge closer.
5. Thus, I think your motion & mine are then complementary and I hope
you will resubmit it soon.
John