Peaks and troughs in the spatial distributions of population, employment and wealth are a universal phenomenon in search of a general theory. Such spatial imbalances have two possible explanations. In the first one, uneven economic development can be seen as the result of the uneven distribution...

Recent trade theory in the Krugman (1980) tradition predicts that countries with larger market size enjoy higher levels of total factor productivity (TFP) - and equivalently of real per capita income or welfare - as a smaller fraction of spending on inputs is affected by trade costs. However, in...