Exact solutions in cosmology based on nonliniar sigma-models

The method of exact analysis of cosmological dynamics at the early inflation stage of the evolution of the Friedman Universe and at the stage of repeated accelerated expansion based on two-component chiral cosmological models is considered. The basis of the method is the reduction of the equations of dynamics to similar to the case of models with one scalar field, by means of conformal transformations of the internal field's space metric.