Find the general conditions such that punishment can work in a linear public good game in the ERC model and the Fehr-Schmidt model.

Hint: For the ERC model find the level of punishment such that, after she has paid for punishing, Anna will have exactly the social reference point. For the Fehr-Schmidt model find the level of punishment such that the free-rider, Miguel, and punisher, Anna, will end up with the same material payoff.