Re: How to get rid of irrelevant Boolean variables from an expression
- To: mathgroup at smc.vnet.net
- Subject: [mg94885] Re: How to get rid of irrelevant Boolean variables from an expression
- From: Peter Pein <petsie at dordos.net>
- Date: Mon, 29 Dec 2008 06:41:56 -0500 (EST)
- References: <gj55j3$c60$1@smc.vnet.net>
Vlad schrieb: > Hi, > > I need to simplify a Boolean expression that looks like > > x && y || !x && y > > 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 > Try LogicalExpand[]: In[1]:= LogicalExpand[(x && y) || ( !x && y)] Out[1]= y In[2]:= LogicalExpand[2b || ! 2b] Out[2]= True