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Re: Re: More /.{I->-1} craziness

  • To: mathgroup at smc.vnet.net
  • Subject: [mg106549] Re: [mg106526] Re: More /.{I->-1} craziness
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Sat, 16 Jan 2010 06:10:16 -0500 (EST)
  • Organization: Mathematics & Statistics, Univ. of Mass./Amherst
  • References: <200912300915.EAA17299@smc.vnet.net> <hhhmkr$o7g$1@smc.vnet.net> <201001150820.DAA29819@smc.vnet.net>
  • Reply-to: murray at math.umass.edu

The actual (i.e., FullForm) representation of I is Complex[0,1] whereas 
the actual (i.e., FullForm) representation of E is and of Pi is Pi.

But it's not even an issue of what happens to a single-character symbol. 
As discussed in previous posts, the FullForm of 2 Pi I, e.g., is 
Times[Complex[0,2],Pi] -- and, more generally, the FullForm of 2 k I is 
Times[Complex[0,2],k].

The issue is not whether something is or is not a single letter.  The 
issue is whether something has a FullForm whose head is Complex.

That's the way it is.  You don't like it.  By now everybody knows you 
don't like it.  But that's the way it is.  What's the point of 
complaining about it again and again and again and again???


On 1/15/2010 3:20 AM, AES wrote:
> In article<hhhmkr$o7g$1 at smc.vnet.net>,
>   Murray Eisenberg<murray at math.umass.edu>  wrote:
>
>> To my mind, the only possible surprise here -- simply because I never
>> looked at it before, concerns -Infinity.  But anything concerning
>> infinite quantities is bound to be so special that nothing about
>> handling of Infinity would really surprise me.
>
> Agreed -- I'd also be extremely cautious in that limit.  But I behaving
> differently (AFAIK) from every other single-character symbol in the
> alphabet?  (esp. E and Pi)
>

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305


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