Named in honor of Margarita Sergeevna Petrovskaya, staff member of the Institute of Theoretical Astronomy since 1960. She determined the domains of convergence of series representing periodic solutions in planetary and satellite problems and obtained a new expansion for the perturbing function that converges even in the case of overlapping orbits. She was the first to construct convergent global expansions for the earth’s potential. (M 30476) _ _.