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Re: Re: Problem Replacing part of NonCommutativeMultiply

  • To: mathgroup at smc.vnet.net
  • Subject: [mg104579] Re: [mg104514] Re: Problem Replacing part of NonCommutativeMultiply
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Wed, 4 Nov 2009 01:36:23 -0500 (EST)
  • References: <hcl3s1$bvc$1@smc.vnet.net> <200911030751.CAA01007@smc.vnet.net>
  • Reply-to: drmajorbob at yahoo.com

Or, if you don't want to risk Unprotect:

g ** a ** p ** r ** e ** r ** e /.
  NonCommutativeMultiply[___, r, e, r, e, ___] :> 0

0

Bobby

On Tue, 03 Nov 2009 01:51:17 -0600, magma <maderri2 at gmail.com> wrote:

> On Nov 1, 11:59 pm, Iv=E1n Lazaro <gamins... at gmail.com> wrote:
>> Dear all,
>>
>> I'm working with a huge amount (2000) of terms of this tipe:
>> g**a**p**r**e**r**e
>>
>> But a lot of them are cero. The problem is that i'm not able to set
>> r**e**r**e->0 in such expresions. If I do  
>> g**a**p**r**e**r**e/.r**e**r**e->0
>> nothing happens.
>>
>> Do you have some idea?
>>
>> Thanks a lot!
>
> Try this:
>
> NonCommutativeMultiply // Unprotect
> NonCommutativeMultiply[x___, 0, y___] := 0
> g ** a ** p ** r ** e ** r ** e ** f ** h /. r ** e ** r ** e -> 0
>
> et voila'...you get 0
>


-- 
DrMajorBob at yahoo.com


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