This paper studies the evolution of the distribution of firms in the ferrous metals industry by efficiency levels. The proposed model takes into account interaction of processes of creation and adoption of technologies and depreciation of assets. It is shown that the model approximates real data...

We propose a difference-differential equation that reflects interactions between innovation and imitation processes to describe the evolution of the distribution curve of firms by efficiency levels. An explicit solution of this equation is obtained for arbitrary finite initial conditions. It is...