Re: global real variables
- To: mathgroup at smc.vnet.net
- Subject: [mg22039] Re: global real variables
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 11 Feb 2000 02:38:20 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <87trds$5o3@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
my Mathematica 4.0.1 reply for
FullSimplify[Conjugate[x + x*p^-1], Element[{x, p}, Reals]]
(1 + p^(-1))*x
But I agree that the Element relation should be an attribute to
a symbol. The best thing is to make a global variable
$mydomains={Element[{x,p},Reals] && Element[{i,j,k},Integers]}
and use
Simplify[expr,$mydomains]
during your calculation. Manly to avoid that you simplify with
the assumption x is real and two steps later you forgot this.
Hope that helps
Jens
>
> Say I have tow var.s, x and p. Both are real so I can do this.
>
> Simplify[ Conjugate[ x ] , Element[ x , Reals ] ] ----> x
>
> amd I get the same thing for p, but it stops working if I have functions of
> x and p, for instance I get
>
> Simplify[ Conjugate[ x + x * p^-1 ] , Element[ {x,p} , Reals ] ] ---->
>
> Conjugate[ x + x * p^-1 ]
>
> It works if I use FullSimplify AND put p^-1 into the list of variables
> that I want to have real. How can I get around this without listing every
> negative power of every variable and wasting time with FullSimplify. Thanks
> for any help. Thanks.
>
> -NAUM