Per capita incomes across European regions are not equal and do not stay constant; regional income distributions uctuate over time. Such a process could have many possible limiting outcomes: complete equal- ity (convergence), stratication, and continually increasing inequality are but three...

Nonparametric regression is developed for data with both a temporal and a cross-sectional dimension. The model includes additive, unknown, individual-specific components and allows also for cross-sectional and temporal dependence and conditional heteroscedasticity. A simple nonparametric...