Rybczynski theorem

It states that at constant relative goods prices, a rise in the endowment of one factor will lead to a more than proportional expansion of the output in the sector which uses that factor intensively, and an absolute decline of the output of the other good.

Eventually, across both countries, market forces would return the system toward equality of production in regard to input prices such as wages (the state of factor price equalization).

The Rybczynski theorem displays how changes in an endowment affects the outputs of the goods when full employment is sustained.

The theorem is useful in analyzing the effects of capital investment, immigration and emigration within the context of a Heckscher-Ohlin model.

In general, an increase in a country's endowment of a factor will cause an increase in output of the good which uses that factor intensively, and a decrease in the output of the other good.