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

• To: mathgroup at smc.vnet.net
• Subject: [mg106298] Re: More /.{I->-1} craziness
• From: Vince Virgilio <blueschi at gmail.com>
• Date: Thu, 7 Jan 2010 02:34:10 -0500 (EST)
• References: <200912300915.EAA17299@smc.vnet.net> <hhhmn8$o9t$1@smc.vnet.net>

On Jan 6, 5:59 am, Richard Fateman <fate... at cs.berkeley.edu> wrote:

SNIP

>
> What I would say is
>
> Because of the disparity in internal representations (see below) ,
> for replacements on parts of complex expressions, don't use /. ...  
> use  /. BetterRules[ ...]
>

This expects too much from ReplaceAll.

> or use transformation or selection programs such as Conjugate, Im, Re, .. .
>

Yes. Not unlike something Andrzej said elsewhere about
PolynomialReduce (others said similar as well).

SNIP

Vince Virgilio

(
Incidentally, my FullForm of x+4*I differs from yours, if I read yours
correctly:

In[1]:= x+4I//FullForm
Out[1]//FullForm= Plus[Complex[0,4],x]
)