Start-ups in different industry groups are classified according to their average complexity. We find that thick regional input markets are conducive to start-up activity in general and complex start-ups in particular, but that some inputs are more important than others.

A growing body of empirical evidence shows that there exists a long-run positive trade-off between inflation and real macroeconomic activity. Within a New Keynesian framework, we examine how increasing returns generate a positive long-run relation between inflation and output.