Re: Logical Expression
- To: mathgroup at smc.vnet.net
- Subject: [mg73432] Re: [mg73385] Logical Expression
- From: János <janos.lobb at yale.edu>
- Date: Fri, 16 Feb 2007 01:01:58 -0500 (EST)
- References: <200702150956.EAA04579@smc.vnet.net>
On Feb 15, 2007, at 4:56 AM, Martin Schoenecker wrote: > Common sense tells me that the statement that "something is equal to > zero, and unequal to zero at the same time" is a false statement: > > In[1]:= a == 0 && a != 0 > Out[1]= a\[Equal]0&&a=E2=89=A00 > > In[2]:= LogicalExpand[%] > Out[2]= False > > The same, in my opinion, applies to "something is equal to zero and > greater than zero at the same time". Why doesn't Mathematica think > so, > and how to convince it to evaluate the following? > > In[3]:= a == 0 && a > 0 > Out[3]= a\[Equal]0&&a>0 > > In[4]:= LogicalExpand[%] > Out[4]= a\[Equal]0&&a>0 > > > Thanks in advance, > Martin Here is a newbie convince :) In[15]:= Reduce[a == 0 && a > 0, a] Out[15]= False J=E1nos ---------------------------------------------- Trying to argue with a politician is like lifting up the head of a corpse. (S. Lem: His Master Voice)
- References:
- Logical Expression
- From: Martin Schoenecker <ms_usenet@gmx.de>
- Logical Expression