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Re: with 5.2 Mac

  • To: mathgroup at smc.vnet.net
  • Subject: [mg59783] Re: with 5.2 Mac
  • From: sbjensen at midway.uchicago.edu (Steuard Jensen)
  • Date: Sun, 21 Aug 2005 03:51:31 -0400 (EDT)
  • Organization: The University of Chicago
  • References: <de6lnl$cfa$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

[Reversed order of quotes to make the discussion easier to read:]

> From: Steuard Jensen [mailto:sbjensen at midway.uchicago.edu]
To: mathgroup at smc.vnet.net
> > I've just upgraded from Mathematica 5.0 to 5.2 for the Mac...

> > Specifically, I have used $Assumptions to define some variables as
> > real.  I apply Conjugate to various expressions, and then Simplify
> > the results.  In version 5.0, I _never_ saw a case in which
> > Conjugate[] remained after this step.  But in 5.2, I find that
> > even simple forms like Conjugate[x + I y] often remain
> > unsimplified.  (Refine[x + I y] still seems to work, though.)

Quoth "David Park" <djmp at earthlink.net> in article
<de6lnl$cfa$1 at smc.vnet.net>:
> Why don't you use...
> 
> ComplexExpand[Conjugate[x + I y]]
> x - I*y
> 
> and you don't even have to set $Assumptions?

That would be an excellent suggestion for this case, but my actual
work isn't this simple.  In particular, my actual expressions include
a mix of complex-valued and real-valued terms.  So either I would have
to use $Assumptions as I've done here, or I would have to pass a long
list of complex variables to ComplexExpand each time.  (And it's even
possible that my extra TransformationFunctions might replace
combinations of complex variables with real ones, so I might have to
use ComplexExpand more than once.)

In any case, whether or not ComplexExpand is the _best_ way to do
this, I think that Simplify still ought to work as expected! :)

Nevertheless, thanks for your suggestion; even if it's not right for
this problem, it could be useful for others.

						Steuard Jensen


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