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Re: How to get rid of irrelevant Boolean variables from an expression

  • To: mathgroup at smc.vnet.net
  • Subject: [mg94889] Re: [mg94828] How to get rid of irrelevant Boolean variables from an expression
  • From: "Jose Luis Gomez" <jose.luis.gomez at itesm.mx>
  • Date: Mon, 29 Dec 2008 06:42:40 -0500 (EST)
  • References: <200812271204.HAA12519@smc.vnet.net>

Simplify[x && y || !x && y]

For larger and more complex expressions you might have to use =
FullSimplify[x
&& y || !x && y]

HTH
Jose
Mexico

-----Mensaje original-----
De: Vlad [mailto:vladtarko at gmail.com]
Enviado el: S=E1bado, 27 de Diciembre de 2008 06:05
Para: mathgroup at smc.vnet.net
Asunto: [mg94828] How to get rid of irrelevant Boolean variables from an
expression

Hi,

I need to simplify a Boolean expression that looks like


to y alone. I.e. the expression's truth value is independent of x so it
should be left out.

I've tried about every Mathematica function for dealing with Boolean
expressions and couldn't do this. Also,

Equivalent[x && y || !x && y, y]//TautologyQ

gives False. This might be because the two expressions don't have the =
same
number of variables (?).

I have large truth tables so I would like to get rid of the irrelevant
Boolean variables automatically. Does anyone know how to do this?

Thanks





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