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Re: Canonical order...

  • To: mathgroup at smc.vnet.net
  • Subject: [mg55041] Re: [mg54989] Canonical order...
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Thu, 10 Mar 2005 05:24:52 -0500 (EST)
  • References: <200503091134.GAA06921@smc.vnet.net> <caec416ba0760044b7e5574d02bf3213@mimuw.edu.pl> <20050309183419.GK42275@genius.tao.org.uk>
  • Sender: owner-wri-mathgroup at wolfram.com

On 9 Mar 2005, at 19:34, Josef Karthauser wrote:

> On Wed, Mar 09, 2005 at 07:09:31PM +0100, Andrzej Kozlowski wrote:
>>
>> Note that changing the behaviour of Sort in this way will have no
>> effect on the behaviour of Times.
>>
>
> Thanks for the reply.
>
> I guess the more basis question is one of canonical order.  Functions
> (like Times) that are attributed with Orderless reorder their arguments
> according to some form of canonicalisation.  In my case I have a
> data-type where I have a different idea of the canonical than 
> mathmatica
> has and I was wondering how to influence mathematica in deciding when
> things are canonical.  Is this possible?
>
> Joe
> -- 
> Josef Karthauser (joe at tao.org.uk)	       http://www.josef-k.net/

You can use any custom sort function for sorting  and some polynomial 
algebra functions let you specify the ordering of variables etc, for 
the purpose of symbolic computation but you can't change Mathematica's 
canonical order in general and in particular you can't change the way 
the Orderless attribute works.

Andrzej


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