Most incomes underlie some risk, i.e. ex ante they can be regarded as a lottery ticket. In every society, the lucky winners of this lottery compensate unlucky losers (unemployed workers or bankrupt entrepreneurs) privately and/or by public insurances. Do voluntary solidarity payments depend on...

The launch of a public project requires support from "enough" members of a group. Members (players) are differently important for the project and have different cost/benefit relations. There are players who profit and players who suffer from the launch of the project. Examples are the Kyoto...