# Automatic calculation of Feynman loop-diagrams I. Generation of a simplified form of the amplitude

## Description

Abstract In order to develop an automatic system to calculate loop diagrams in renormalizable theories, we present the first part of a complete system written in REDUCE and RLISP. It can generate the tensor and gamma matrix basis which is able to cast the total amplitude into a simpler form with the help of gauge invariance and symmetry among identical particles. Title of program: FDC1 Catalogue Id: ACNY_v1_0 Nature of problem In perturbative field theory, calculation of Feynman loop-process become more and more complicated and tedious as higher order correction is taken into account. Therefore, to develop programs to perform the work automatically become very useful. To construct a practicable program, there are many obstacles, such as how to express total amplitude to obtain the amplitude square, Feynman parameter integration, etc. Versions of this program held in the CPC repository in Mendeley Data ACNY_v1_0; FDC1; 10.1016/0010-4655(93)90010-A This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)