Us travel places for While Nash proved that all finite games have an equilibrium point, they frequently possess more than one. This multiplicity makes additional selection criteria desirable. Selten was the first to systematically put further restrictions on Nash's Equilibrium concept, in order to identify reasonable predictions. Selten's most celebrated contributions are the solution concepts of Trembling Hand Perfect Equilibrium and Subgame Perfect Equilibrium. In the former, each player's strategic choice must be optimal even when there is a small chance that other players make mistakes (that is, they do not play their optimal strategies). The latter applies to strategic situations with a dynamic structure, requiring that each player's choice involves only threats and promises of future actions that are credible, in the sense that they are optimal once a player must make his decision. Selten showed that all finite games have such equilibria. Us travel places 2016.