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Re: Bug: symbol recreates itself suddenly

  • To: mathgroup at smc.vnet.net
  • Subject: [mg86809] Re: Bug: symbol recreates itself suddenly
  • From: "Severin Posta" <severin at km1.fjfi.cvut.cz>
  • Date: Fri, 21 Mar 2008 01:56:25 -0500 (EST)
  • Organization: Czech Technical University
  • References: <9457525.1205860522819.JavaMail.root@m08> <frqpu5$59m$1@smc.vnet.net>

This is definitely NOT the correct answer. The correct answer is (should be)

"Symbol E not found."

By all means this is really a bug.

It has far-reaching consequences. Using symbol E afterwards can lead to 
mistakes because Mathematica thinks (suddenly!) this is again Euler 
constant, not general symbol.



Please don't ask why am I doing this. This is not forbidden according to 
manual - and it worked in 4.0, 5.0, 5.2 versions. It should work in 6.0 
either. (Or it should be documented.)

Severin Posta

"DrMajorBob" <drmajorbob at bigfoot.com> wrote in message 
news:frqpu5$59m$1 at smc.vnet.net...
> "In[6]:= ?E
>
> E is the exponential constant e (base of natural logarithms), with \
> numerical value \[TildeEqual]2.71828. >>
>
> (* THIS IS NOT CORRECT ANSWER *)"
>
> Oh yes, it certainly IS the correct answer.
>
> Why do you want to Remove built-in constants? (Regardless of whether it
> might or might not "work" to do so?)
>
> Bobby
>
> On Tue, 18 Mar 2008 04:50:49 -0500, Severin Posta
>
> <severin at km1.fjfi.cvut.cz> wrote:
>
>> It seems to me that after Remove[symbol] some times the symbol is
>> "recreated" without notice. Consider the following example.
>>
>> How to repeat:
>>
>> In[1]:= $Version
>>
>> Out[1]= "6.0 for Microsoft Windows (32-bit) (April 20, 2007)"
>>
>> In[2]:= Unprotect[E]; ClearAttributes[E, {Constant, Protected,
>>
>> ReadProtected}]; Remove[E];
>>
>> In[4]:= ?E
>>
>> During evaluation of In[4]:= Information::notfound: Symbol E not
>> \ found. >>
>>
>> In[5]:= Solve[E == 2]
>>
>> Out[5]= {{Global`E -> 2}}
>>
>> (* ?! *)
>>
>> In[6]:= ?E
>>
>> E is the exponential constant e (base of natural logarithms), with \
>> numerical value \[TildeEqual]2.71828. >>
>>
>> (* THIS IS NOT CORRECT ANSWER *)
>>
>>
>>
>> Severin Posta
>>
>>
>>
>>
>>
>>
>
>
>
> -- =
>
> DrMajorBob at longhorns.com
> 




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