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Re: Why doesn't TrueQ return True here?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg119745] Re: Why doesn't TrueQ return True here?
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Mon, 20 Jun 2011 08:05:06 -0400 (EDT)
  • Reply-to: hanlonr at cox.net

??$Assumptions

$Assumptions is the default setting for the Assumptions option used in such functions as Simplify, Refine and Integrate. =C2 >>

$Assumptions=True


TrueQ is not one of the functions that makes use of $Assumptions.

$Assumptions = t2 > t1;

Simplify[(t2 - t1) > 0]

True

TrueQ[Simplify[(t2 - t1) > 0]]

True


Bob Hanlon

---- Jacare Omoplata <walkeystalkey at gmail.com> wrote:

=============
Here's the output.
-------------------------------------------------------
In[29]:= Element[{t1, t2}, Reals]

Out[29]= (t1 | t2) \[Element] Reals

In[30]:= $Assumptions = t2 > t1

Out[30]= t2 > t1

In[31]:= TrueQ[(t2 - t1) > 0]

Out[31]= False
------------------------------------------------------

I would expect TrueQ to return True, not False. Why does it return False?

And how can I test whether t2-t1 is positive?

Thanks.



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