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MathGroup Archive 2002

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Solve/Reduce and assumptions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg32887] Solve/Reduce and assumptions
  • From: Hiranya Peiris <hiranya at astro.princeton.edu>
  • Date: Mon, 18 Feb 2002 05:22:08 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

I have a large set of simultaneous multivariate algebraic equations which
I am solving using Solve and Reduce. I get as the answer a list of all
possible sets of solutions. However, only one of these is valid, because
the equations contain a constant parameter R which should be positive. I
cannot find any way of getting Solve and Reduce to recognize this fact.
For example,

Solve[{eqn1,eqn2,...eqnN,R!=0},vars] works, while

Solve[{eqn1,eqn2,...eqnN,R>0},vars] is invalid.

Applying

Simplify[Result,R>0]

to the full solution set does not work either.

I would be grateful for any advice on how to get around this. I am a
newbie, and I tried everything I could think of - mailing this list is my
last resort.

Please copy any replies to my email address: hiranya at astro.princeton.edu

Thanks very much!
Hiranya



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