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Manuscript Title: Algebraic reduction of Feynman diagrams to scalar integrals: a Mathematica implementation of LERG-I.
Authors: R.G. Stuart
Program title: LERG-I
Catalogue identifier: ABBX_v3_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 85(1995)267
Programming language: Mathematica.
Computer: NeXT Workstation.
Operating system: UNIX.
Word size: 32
Keywords: General purpose, Diagramatic expansions, Computer algebra.
Classification: 4.4, 5.

Revision history:
Type Tit le Reference
correction 000A CORRECTION 28/04/95 See below

Nature of problem:
Expressions obtained in the calculation of one-loop radiative corrections in particle physics are generally simplified by expressing them in terms of scalar integrals. LERG-I reduces the form factors, associated with the various possible Lorentz tensors, occurring in the problem, to scalar integrals.

Solution method:
The program makes use of identities that, in the context of dimensional regularization, relate form factors to one and other in a heirarchical fashion. The end result is that all form factors are finally defined in terms of scalar integrals.

Restrictions:
Processes with up to four external particles can be treated. Machine storage is usually the only limitation.

Running time:
Depends heavily on the complexity of the problem. The examples provided as test runs took roughly 0.2 CPUs to execute.

References:
[1] Mathematica, S. Wolfram, Addison-Wesley (1988)

CORRECTION SUMMARY
Manuscript Title: Algebraic reduction of Feynman diagrams to scalar integrals: a Mathematica implementation of LERG-I. (C.P.C. 85(1995)267).
Authors: R.G. Stuart
Program title: 000A CORRECTION 28/04/95
Catalogue identifier: ABBX_v3_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 88(1995)347
Classification: 4.4, 5.