The past star-formation rate and the initial mass-function in the solar neighbourhood

The present-day mass function and the kinematical data of the nearby stars are discussed as constraints on the time-behaviour of the star-formation rate and of the initial mass function during the evolution of the galactic disk. A recently suggested dependence of the initial mass-function slope on the heavy element abundance can not be excluded from this study. The average past star-formation rate is in the order of the present-day rate.Paper presented at a Workshop on The Role of Dust in Dense Regions of Interstellar Matter, held at Georgenthal, G.D.R., in March 1986.