Direct questions and comments to: Glossary master
In the most simple games (with complete information and simultaneous moves) the strategy of a player simply specifies which action this player takes. To be general enough to cover also more complex games (like dynamic games of incomplete information), the notion of strategy is very comprehensive: A strategy of a player is a complete plan of action in the game. In particular, for each point of time where the player is called upon to act, it describes which action to choose. And it does so for every combination of previous moves (of this player and of his opponents) and for each type of player.
For example, in a dynamic game like chess, a strategy specifies not only the move of a player in the first round, but also in every consecutive round for every possible combination of previous rounds (e.g. if a strategy in a suitable game specifies that a player commits suicide today, it must also specify what he would do tomorrow if he still were alive.)
In games of incomplete information there are different types of players, e.g. in auctions there are types with different valuations for the object for sale. Here a strategy specifies a complete plan of action for every such type.
Mixed strategy: In contrast to pure strategies, mixed strategies are strategies that involve random draws. A mixed strategy is a probability distribution over a player's (pure) strategies. For example in penalty shooting, the goalgetter typically does not expect the goalkeeper to jump to the right corner for sure, but he regards the goalkeeper's behaviour as a mix between the pure strategies "jump to the right" and "jump to the left".
See also: decision strategies (in the social sciences), dominant strategies
Literature: Gibbons (1992)
| Entry by: Karsten Fieseler |
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December 1, 1997 Direct questions and comments to: Glossary master |
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