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On Wed, 19 May 2004, Bob McElrath wrote:

Dear Bob,

thank you for your explanation. Are there Hopf algebra methods and

recently made advances also implemented in FeynCalc? The package Rafal and

I developed, benefitted is speed and conceptual design cery much from Hopf

algebraic techniques.

From a technical point of view, its algorithmically more sound to

try to work in the Epstein-Glaser (etc pp) framework and *not* in the

momentum (Feynman graph) picture, since the physical process is split up

in an infinite series of integrals to be evaluated. AFAIK Hopf algebraic

techniques seem to be the only way to come up with concise _and_

algorithmically effective solutions.

I am off for three weeks, and will look into FeynCalc, I can

imagine to help withits portation to AXIOM though for several personal

reasons. If you are interested in the things I have in mind, you may

consider the recent JPysA article on Quantum fieldtheory and Hopf algebra

cohomology, by Brouder,BF,Frabetti and Oeckl. Many of the calculations

there were checked by the above mentioned package, though it was _not_

designed for that purpose.

ciao,

BF.

PS:

*> The "algorithms" are documented in QFT textbooks such as Peskin &
*

*> Schroeder
*

Would you really make this a claim? I still think, that without expert

knowledge one cannot derive even simple results out of these sources...

% PD Dr Bertfried Fauser

% Institution: Max Planck Institut for Mathematics Leipzig <http://www.mis.mpg.de>

% Privat Docent: University of Konstanz, Physics Dept <http://www.uni-konstanz.de>

% contact |-> URL : http://clifford.physik.uni-konstanz.de/~fauser/

% Phone : Leipzig +49 341 9959 735 Konstanz +49 7531 693491

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