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Re: Relational operators on intervals: bug?


On Nov 14, 2012, at 5:39 AM, Andrzej Kozlowski <akozlowski at gmail.com> wrote:

>
> On 14 Nov 2012, at 07:28, Richard Fateman <fateman at cs.berkeley.edu> wrote:
>
>> On 11/12/2012 9:13 PM, Murray Eisenberg wrote:
>>
>>>
>>> Here is the empty interval in Mathematica:
>>>
>>>  Interval[{1, 0}]
>>>
>>> Indeed:
>>>
>>>   Resolve[Exists[x, IntervalMemberQ[Interval[{1, 0}], x]]]
>>> False
>>>
>> Apparently this doesn't mean what you think it does. It gives the same
>> answer for Interval[{0,1}].
>
> Of course that is because
>
> IntervalMemberQ[Interval[{0, 1}], x]
>
> False

What remains surprising to me is:

   Resolve[Exists[x, x \[Element] Reals, IntervalMemberQ[Interval[{0, 1}], x]]]
False

---
Murray Eisenberg                           murray at math.umass.edu
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University of Massachusetts                      413 545-2838 (W)
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