Re: Symbolic complex conjugation?

*To*: mathgroup at smc.vnet.net*Subject*: [mg89944] Re: [mg89919] Symbolic complex conjugation?*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Wed, 25 Jun 2008 06:24:21 -0400 (EDT)*References*: <200806240731.DAA11098@smc.vnet.net>

On 24 Jun 2008, at 16:31, AES wrote: > I'm sorry, but I just don't understand why the following test case > works > just fine: > > [In copying it, I've substituted "Isymbol" for the \[ImaginaryI] that > actually appears in the Out[] cells.] > > In[202]:= eqna={a+I b==0}; > solna=Solve[eqna,b]; > b=b/.solna[[1]]; > bStar=b/.{I->-I}; > {b, Star} > > Out[205]={ -Isymbol a, Isymbol a } > > but the actual calculation that prompted the test case doesn't: > > In[206]:= eqnp={((dwa/2)+I(w-wa))p-I (kappa/(2 w))dN e==0}; > solnp=Solve[eqnp,p]; > p=p/.solnp[[1]]; > pStar=p/.{I->-I} > > Out[208]= { (dN e kappa)/(w (-Isymbol dwa+2 w-2 wa)), > (dN e kappa)/(w (-Isymbol dwa+2 w-2 wa)) } > > And actually, I guess my real concern is not understanding "how it > happens" -- but more "how it can happen" that Mathematica can do > something this potentially damaging to some innocent user. > Because Mathematica is not meant and has never been meant as a tool for "innocent users" who try to use pattern matching without learning about FullForm of expressions. Such users would be well advised to use instead a graphic calculator or its software equivalent. For those who are not entirely innocent the following solution is obvious: pStar = p/.Complex[a_,b_]:>Complex[a,-b] Andrzej Kozlowski

**References**:**Symbolic complex conjugation?***From:*AES <siegman@stanford.edu>