ON the question of the uniqueness of the energy-momentum complex in the special and general theory of relativity

Modification of the Fock method is used to look systematically for the complexes of energy and momentum which are conserved as a consequence of the vacuum field equations of the second order (real and complex scalar field, real vector field, symmetric tensor field of the linearized and non-linear Einstein theory). In contrast to Fock's results for fields described by equations of the first order, the complexes are not defined uniquely. The non-uniquenesses are eliminated by supplementary conditions.This paper is based on a diploma thesis worked out at the Department of Theoretical Physics, Faculty of Mathematics and Physics, Charles University.