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Re: Common factors in a list


Mathematica will just undo the operation since the multiplication is automatic

expr1=a*{x,y,z}

{a x,a y,a z}

You can use a dummy operator such as CircleTimes

expr2=expr1/.{a_*x_,a_*y_,a_*z_}:>
      CircleTimes[a,{x,y,z}]

a ? {x, y, z}

And clear it with

expr2/.CircleTimes:>Times

{a x,a y,a z}


Bob Hanlon

> 
> From: "John Reed" <nospamjreed at alum.mit.edu>
To: mathgroup at smc.vnet.net
> Date: 2005/06/28 Tue AM 05:13:27 EDT
> Subject: [mg58338] [mg58327] Common factors in a list
> 
> I'm working with a list (vector) that's composed of functions such as 
> complex exponentials and Bessel functions.  Some of the functions are 
common 
> to each element of the list.  I'm trying to find a way to do the following:
> 
>    {a x, a y, a z}-> a *{x, y, z}
> 
> In this expression, a, x, y, z are polynomials, exponentials and/or Bessel 
> functions.
> 
> So far I haven't had any luck with this.  Does anyone have a simple 
> solution?
> 
> John Reed 
> 
> 


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