我的想法
公共商品，排他性、外部性，所谓是一旦被生产出来，那么在一定范围之内，每个人都会因此收益。
The public goods have 2 features, one is Nonrival and another is Nonexclusive
| Exclusive | Non-Exclusive | |
|---|---|---|
| Rivalry | Private Goods | Common Pool Resources |
| Non-Rivalry | Club Goods | Private Goods |
Problems
The public goods will also face some problems, because since we know everyone would benefit from the public goods. So that everyone could have the incentive to be a Free-Rider, then there would be some methods regarding to the Game Theory .
Roommate problem
In this game, both roommates would choose not to clean the room. (although they are willing to get a clean room). However, this situation is inferior to which both roommates clean the room, so there need a Pareto Improvement to force them to do so. Like Compulsory Taxation. It’s like a prisoners’ dilemma which is far from the Pareto Optimality