An elementary proposition on technical progress and non-traded goods

We explore the effect of technical progress on the endogenously determined range of non-traded goods by using a Ricardian model with continuum of goods. By defining technical progress on the basis of proportional changes in the relative productivity across sectors, we show that the range of non-traded goods decreases if technical progress is unbiased or if it is biased toward the goods that a country has more comparative advantage.