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Re: Negation of Negation wanted

• To: mathgroup at smc.vnet.net
• Subject: [mg44048] Re: Negation of Negation wanted
• From: "Peter Pein" <nospam at spam.no>
• Date: Sun, 19 Oct 2003 01:10:46 -0400 (EDT)
• References: <200310180712.DAA28017@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

What about

In[1]:=
f[x1_, x2_] := x1 && x2; 
LogicalExpand[ !f[ !a,  !b]]
Out[2]=
a || b
?

Peter Pein, Berlin
petsie at arcAND.de
replace && by || to write to me


----- Original Message ----- 
From: "Thomas Gutzler" <gutzler at itiv.uni-karlsruhe.de>
To: mathgroup at smc.vnet.net
Subject: [mg44048]  Negation of Negation wanted


> Hi,
> 
> Assuming f(x) = x1 && x2
> 
> Is there a way to get !f(!x), which is:
> !(!x1 && !x2) = x1 || x2
> without copy&paste and manually change it?
> 
> Cheers,
>    Tom
> 

• References:
  • Negation of Negation wanted
    • From: Thomas Gutzler <gutzler@itiv.uni-karlsruhe.de>