The provision point mechanism with refund bonuses

We introduce refund bonuses into the provision point mechanism. If a total contribution is less than the provision point, each contributor receives not only his contribution refunded but also a refund bonus the size of which is proportional to the contribution made. However, because of competition for refund bonuses the provision point is reached in equilibrium. Furthermore, the mechanism can uniquely implement the public good project with Lindahl prices. The mechanism also has other applications.