Construction of limiting relations for many-time averages

Under certain fairly general additional conditions, theorems are formulated which make it possible to calculate many-time correlation averages and also chronological products of Green's functions constructed on the basis of these averages. Particular attention is devoted to the possibility of obtaining majorizing estimates that are uniform in the temperatare. The method developed is valid for a large class of model systems characterized by a Hamiltonian with a four-fermion interaction.