Theory of asymptotic operation. A summary of basic principles
Abstract
Description
This summary of several talks given in 1990-1993 discusses the problem of asymptotic expansions of multiloop Feynman diagrams in masses and external momenta - a central problem in perturbative quantum field theory. Basic principles of the theory of asymptotic operation -- the most powerful tool for that purpose -- are discussed. Its connection with the conventional methods is explained (the BPHZ theory, the method of leading logarithmic approximation etc.). The problem of non-euclidean asymptotic regimes is discussed as well as ways of its solution.
29p PS. Earlier versions of the same text in: Workshop "New Calc. Techniques (ETH, 1992)" and Sov.J.Nucl.Phys. 56 (1993) 180. New compared to versions of 1992/3: simple example on pp.12-14. 8-nov-98: maintenance (typos, PS, upd refs). 23-nov-98: missing symbols fixed
29p PS. Earlier versions of the same text in: Workshop "New Calc. Techniques (ETH, 1992)" and Sov.J.Nucl.Phys. 56 (1993) 180. New compared to versions of 1992/3: simple example on pp.12-14. 8-nov-98: maintenance (typos, PS, upd refs). 23-nov-98: missing symbols fixed