New macro empirical evidence is provided to assess the relative importance of object and idea gaps in explaining the world income distribution dynamics. Formal statistical hypothesis tests allow us to discriminate between two competing growthmodels: (i) the standard neoclassical growth model...

This paper extends the class of AK models with an explicit solution to the case where there are two capital goods in the model. this extension holds, even if an external effect in the use of human capital in goods production ia assumed.