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MathGroup Archive 2005

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Re: operators for relations in sets

  • To: mathgroup at
  • Subject: [mg60346] Re: [mg60338] operators for relations in sets
  • From: Andrzej Kozlowski <akoz at>
  • Date: Wed, 14 Sep 2005 03:27:14 -0400 (EDT)
  • References: <>
  • Sender: owner-wri-mathgroup at

On 13 Sep 2005, at 19:07, hawkmoon269 wrote:

> I'm having some difficulty understanding the behaviour of the  
> operators
> for relations in sets in Mathematica.  For instance,
> TrueQ[{1}\[SubsetEqual]{1}]
> returns
> False
> I'm not getting what's going on here...
> h

First of all, \[SubsetEqual] is not defined in Mathematica. You can  
define your own function SubsetEqual as:

SubsetEqual[A_List, B_List] := Intersection[A, B] == A

so that



etc. If you really want with the help of the Notation package you can  
make the infix form A\[SubsetEqual]B equivalent to Subsetequal[A,B]  
(although i would not bother).

As for TrueQ, it serves a completely different purpose. Note that  
TrueQ always gives False whenever something is not explicitly true,  
for example






TrueQ has its uses but your example is not one  of them!.

Andrzej Kozlowski

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