Re: Logical Expression
- To: mathgroup at smc.vnet.net
- Subject: [mg73415] Re: [mg73385] Logical Expression
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Fri, 16 Feb 2007 00:52:42 -0500 (EST)
- Reply-to: hanlonr at cox.net
Use Simplify Simplify[a == 0 && a > 0] False Bob Hanlon ---- Martin Schoenecker <ms_usenet at gmx.de> 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