Existence, uniqueness, and comparative statics of Nash equilibrium in a game of voluntary public good provision with two public goods

This paper shows the uniqueness of a Nash equilibrium in the presence of many heterogeneous players with two public goods under Cobb–Douglas preferences. It provides a sufficient condition for a unique equilibrium including contributors providing both public goods, and shows that contributors providing both public goods appear frequently. This uniqueness property allows us to conduct a comparative statics analysis with a contributor and a free rider of both public goods, showing the role of the contributor providing both public goods.