[GiNaC-devel] indexes of clifford objects

[Richard B. Kreckel]

Dear Vladimir,

On 06/05/2011 06:55 AM, Vladimir V. Kisil wrote:
>>>>>> On Sun, 05 Jun 2011 00:19:51 +0200, "Richard B. Kreckel"<kreckel at ginac.de>  said:
>      RK>   From a physicists point of view, I thought that it doesn't make
>      RK>  sense to construct a clifford object with an idx instead of a
>      RK>  varidx.
>
> 	There are several mathematical frameworks leading to Clifford
>    algebras. Most elementary one is a free algebra with n generators
>    factorised by an ideal of the quadratic (anticommuting)
>    relations. From that perspective generators of the Clifford algebra
>    are not required to be even indexed objects at all. You may call them
>    simply a, b, c,... as long as you able to make manipulations like ab=-ba,
>    a^2=-1, etc.

Thanks for the concise reminder.

>      RK>  If someone with more insight could shed a light on this I could
>      RK>  finish my recent quest to make GiNaC pass its test suite even
>      RK>  when compiled with -DDO_GINAC_ASSERT. That would be great.
>
> 	However, I do not see a practical obstacle to change the GiNaC code
>    to permit varidx only as indices in the clifford class.

That, as opposed to making the clifford constructor accept both varidx 
and idx, would require changes to clifford_moebius_map and to the 
tutorial. Either way, can you recommend a patch?

   -richy.
-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>