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Re: Questions about assumptions

  • To: mathgroup at
  • Subject: [mg101793] Re: [mg101749] Questions about assumptions
  • From: Bob Hanlon <hanlonr at>
  • Date: Fri, 17 Jul 2009 05:04:04 -0400 (EDT)
  • Reply-to: hanlonr at

$Assumptions = Element[g, Reals];

Look in Help for $Assumptions. Conjugate does not use $Assumptions, you need to use Simplify or FullSimplify



Bob Hanlon

---- Alexander Erlich <alexander.erlich at> wrote: 


I would like to make assumptions like e.g. Element[a,Reals] or b>0 or
simlar ones global in order to avoid using Refine with long assumption
lists every tome. For this purpose, I've found $Assumptions. But I
encountered the following problem:

In[5]:= $Assumptions = Element[g, Reals]

Out[5]= g \[Element] Reals

In[6]:= Conjugate[g]

Out[6]= Conjugate[g]

Why didn't Mathematica just return g?

Maybe, there is a different, or even better way to make assumptions
global to the whole notebook, so that they are considered
automatically (and without Refine or similar)?



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