Cosmological status of Lagrangian theory of density perturbations

Abstract

We show that hydrodynamical and field approaches in theory of cosmological scalar perturbations are equivalent for a single medium. We also give relations between notations introduced by V. Lukash, J. Bardeen, J. Bardeen et al. and G. Chibisov and V. Mukhanov.

8 pages, no figures, submitted to Astronomy Reports