Re: Incomplete simplification
- To: mathgroup at smc.vnet.net
- Subject: [mg49293] Re: Incomplete simplification
- From: BobHanlon at aol.com
- Date: Mon, 12 Jul 2004 02:11:34 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Simplify works with this on my version
$Version
5.0 for Mac OS X (November 19, 2003)
S={{0,-x31,x21},{x31,0,-x11},{-x21,x11,0},{0,-x32,x22},{x32,0,-x12},{-x22,x12,
0}};
G=PseudoInverse[S];
G1=Simplify[G, Element[Cases[S, _Symbol,Infinity], Reals]];
G2=ComplexExpand[G];
G1==G2 // Simplify
True
Bob Hanlon
> In a message dated Sun, 11 Jul 2004 06:26:30 +0000 (UTC),
> carlos at colorado.edu writes:<BR><BR>Using Mathematica 4.2 on a mac I defined a 6 x 3
> symbolic
> matrix and take its Moore-Penrose inverse:
>
> S={{0,-x31,x21},{x31,0,-x11},{-x21,x11,0},{0,-x32,x22},
> {x32,0,-x12},{-x22,x12,0}};
> G=PseudoInverse[S];
>
> Mathematica thinks the entries are complex, so it returns a
> result with Conjugate[x11], etc. To get rid of them I tried
>
> G=Simplify[G,x11\[Element]Reals&&x21\[Element]Reals <...> ];
>
> But the Conjugate[...] are still there. Fortunately G=ComplexExpand[G]
> works. But why is Simplify unable to use the reality assumptions?
>