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Re: Usage of **

  • To: mathgroup at smc.vnet.net
  • Subject: [mg84723] Re: Usage of **
  • From: "Michael Weyrauch" <michael.weyrauch at gmx.de>
  • Date: Fri, 11 Jan 2008 04:43:06 -0500 (EST)
  • References: <fm4sh7$c06$1@smc.vnet.net>

Hello,

  of course, you can do that.

You can use **, which is Protected, Unprotect it and give it the properties you need, including
things like  (x*A)**(y*B)=x*y*(A**B)).
Appart from the Attribute Flat, ** does not really have any rules attached, so you need to teach it the rules you want. It is save 
and does not break anything as far as I
have experienced. I use it for implementing Grassmann algebras.

Maybe it is better to use CircleTimes[] instead of **, then it looks more like your o in
printed formulas. CircleTimes is not even Protected.

Michael Weyrauch


"Hauke Reddmann" <fc3a501 at uni-hamburg.de> schrieb im Newsbeitrag news:fm4sh7$c06$1 at smc.vnet.net...
> I'm playing with a Temperley-Lieb algebra with three strings,
> i.e. an operator o, two generators A and B and a scalar t.
> (AoA=t*A,BoB=t*B,AoBoA=A,BoAoB=B.)
> Unluckily, AoB!=BoA, *and* I want to define some "mixes"
> like w*A+x*B+y*AoB+z*BoA and multiply them, o shall be linear.
> So e.g.  (w*A+x*B)oA=w*(AoA)+x*(BoA)=w*A+x*(BoA).
>
> How to implement? With o=** maybe (but does (x*A)**(y*B)
> evaluate to x*y*(A**B)), and can I define "global rules"
> that act automatically, just like I*I=-1)?
>
> -- 
> Hauke Reddmann <:-EX8    fc3a501 at uni-hamburg.de
>    Er-a svo gott     sem gott kveða
>    öl alda sonum,     því að færra veit
>    er fleira drekkur     síns til geðs gumi.
> 



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