Increasing Returns, Public Inputs and Transformation Curves.
This paper shows, that despite the presence of increasing returns to scale caused by a public input, the transformation curve of an economy will be concave to the origin if the market for the public input is Marshall stable. It also shows that when the public input is a natural friend to both labor and capital, Marshallian stability holds if and only if the relative price version of the Stolper-Samuelson theorem holds.