Consider a collective decision between three individuals to produce or not produce one

public good which costs R1500. Suppose that if the public good is produced, the cost is

equally shared between the three individuals. Assume that the gross benefits from the public

good differ between individuals and are respectively R200, R400 and R1000 for individual

1, 2 and 3. Each individual is asked to announce his own benefit for the public good and the

public good is produced only if the sum of the reported benefits is non-negative.

Show that the Groves-Clarke mechanism induces truth telling as a dominant strategy if each

individual reports independently their own benefit.