This paper employs a distribution dynamics approach to examine the empirical dynamics of technological specialisation in industrial countries. Using patent data, cross-sectional distributions at different time periods and Markov stochastic kernels are estimated nonparametrically for each country. Three are the main findings. There is a strong country size effect: economically “large” countries ...

We revisit the work of Dhar and Majumdar [Phys. Rev. E 59, 6413 (1999)] on the limiting distribution of the temporal mean Mt = t −1 ∫ t 0 du sign yu, for a Gaussian Markovian process yt depending on a parameter α, which can be interpreted as Brownian motion in the scale of time t′ = t2α. This quantity, for short the mean ‘magnetization’, is simply related to the occupation time of the process, ...