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Re: Re: Function definition

• To: mathgroup at smc.vnet.net
• Subject: [mg18230] Re: [mg18215] Re: Function definition
• From: "Kevin J. McCann" <kevinmccann at Home.com>
• Date: Thu, 24 Jun 1999 14:24:15 -0400
• References: <7kmtmi$230@smc.vnet.net> <199906230041.UAA04366@smc.vnet.net.>
• Sender: owner-wri-mathgroup at wolfram.com

Here is a further suggestion

 Remove[foo]
foo[x_ /; x \[Element] Reals] := x
foo[x_ /; Im[x] == 0] := x

then
foo[1.234]
1.234

foo[Pi]
Pi

foo[I]
foo[I]

But now you can also do the following:

<< "Algebra`ReIm`"
Re[y] ^= y; 
Im[y] ^= 0; 
Abs[y] ^= y; 

foo[y]
y

so you can define variables to be real.

Kevin

• References:
  • Re: Function definition
    • From: Murray Eisenberg <murray@math.umass.edu>