Re: Negation of Negation wanted
- To: mathgroup at smc.vnet.net
- Subject: [mg44039] Re: Negation of Negation wanted
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Sun, 19 Oct 2003 01:10:33 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On Saturday, October 18, 2003, at 04:12 PM, Thomas Gutzler wrote: > 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 > > > Since you are not using Mathematica syntax (or any other syntax known to me) it is not entirely clear what you mean. However, assuming that you define your f by f[x_,y_]:=Not[x]&&Not[y] you can use LogicalExpand to get: LogicalExpand[Not[f[Not[a],Not[b]]]] !a||!b Andrzej Kozlowski Yokohama, Japan http://www.mimuw.edu.pl/~akoz/ http://platon.c.u-tokyo.ac.jp/andrzej/