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Re: Why does Reduce work this way ...?

• To: mathgroup at smc.vnet.net
• Subject: [mg67236] Re: Why does Reduce work this way ...?
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Wed, 14 Jun 2006 06:28:40 -0400 (EDT)
• Organization: The Open University, Milton Keynes, UK
• References: <e6lhul$nh2$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

jackgoldberg at comcast.net wrote:
> Hi folks,
> 
> This post is related to a previous series of posts about ReplaceAll in a set of inequalities.
> I have "reduced" the problem to this unexpected situation:
> 
> In[1]  FullForm[-3<=x<=1]
> Out[1]  LessEqual[-3,x,1]
> 
> In[2] Reduce[-3<=x<=1]
> Out[2]  -3<=x<=1
> 
> In[3]  FullForm[%2]
> Out[3]  Inequality[-3, LessEqual, y, LessEqual, 1]
> 
> In[4] Reduce[ LessEqual[-3,x,1]
> Out[4] -3 &#8804; x &#8804; 1
> 
> In[5] FullForm[%4]
> Out[5]  Inequality[-3, LessEqual, y, LessEqual, 1]
> 
> This defies my understanding.  What is qoing on with Reduce?
> 
> Jack
> 
Hi Jack,

Yes, your results seem rather puzzling! I don not know from where you 
can possibly get the 'y' especially with a freshly started Mathematica 
session...

On my system everything is fine, no 'y'

In[1]:=
FullForm[-3 <= x <= 1]

Out[1]//FullForm=
LessEqual[-3, x, 1]

In[2]:=
Reduce[-3 <= x <= 1]

Out[2]=
-3 <= x <= 1

In[3]:=
FullForm[%2]

Out[3]//FullForm=
Inequality[-3, LessEqual, x, LessEqual, 1]

In[4]:=
Reduce[-3 <= x <= 1]

Out[4]=
-3 <= x <= 1

In[5]:=
FullForm[%4]

Out[5]//FullForm=
Inequality[-3, LessEqual, x, LessEqual, 1]

In[6]:=
$Version

Out[6]=
5.2 for Microsoft Windows (June 20, 2005)

Best regards,
/Jean-Marc