Re: operators for relations in sets

*To*: mathgroup at smc.vnet.net*Subject*: [mg60346] Re: [mg60338] operators for relations in sets*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Wed, 14 Sep 2005 03:27:14 -0400 (EDT)*References*: <200509131007.GAA09833@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

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 SubsetEqual[{1},{1,2}] True 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[Sin[x]^2+Cos[x]^2==1] False although TrueQ[Simplify[Sin[x]^2+Cos[x]^2==1]] True TrueQ has its uses but your example is not one of them!. Andrzej Kozlowski

**References**:**operators for relations in sets***From:*"hawkmoon269" <rson@new.rr.com>