Buiter (1981) illustrates that in the OLG model, the ranking of stationary utility levels under autarky and openness, is ambiguous. We show that both countries increase their stationary utility levels only if the autarky capital-labor ratios are on opposite sides of the golden rule

Barro's model is an AK model, and there cannot be dynamic ineffciency since the social yield of the capital is higher than the growth rate. But it may be that the private yield and thus the interest rate are lower than the growth rate. One can thus have a Ponzi game and the government can allow...