# What Is Complete Information in Game Theory?

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Martha Robinson

Game theory is a branch of mathematics that studies decision-making in strategic situations where one player’s choice depends on the choices made by other players. Complete information is an important concept in game theory that refers to a situation where each player knows the other players’ preferences, actions, and payoffs.

## What Is Complete Information?

In a game with complete information, every player knows everything there is to know about the game. This includes knowledge of all the other players’ preferences, actions, and payoffs. In other words, there are no hidden or unknown factors that could affect the outcome of the game.

### Examples of Games with Complete Information

One example of a game with complete information is chess. In chess, both players know the rules of the game and can see all of the pieces on the board.

Each player has complete knowledge of their own pieces and their opponent’s pieces. This allows them to make informed decisions and plan their moves accordingly.

Another example of a game with complete information is tic-tac-toe. In tic-tac-toe, both players know all possible moves and outcomes from every position on the board. This means that there are no surprises or hidden information that could affect the outcome of the game.

### Why Is Complete Information Important?

Complete information is important in game theory because it allows players to make rational decisions based on all available information. If one player has incomplete or inaccurate information, they may make suboptimal choices that could lead to a less favorable outcome for themselves.

In games with incomplete information, such as poker or rock-paper-scissors, players must use strategies based on probability and risk assessment rather than complete knowledge of their opponents’ preferences and actions.

### Conclusion

In summary, complete information refers to a situation in which each player has full knowledge of all aspects of a game including other players’ preferences, actions, and payoffs. This concept is important in game theory because it allows players to make informed decisions and avoid suboptimal outcomes. Understanding the concept of complete information can help players develop effective strategies in a variety of games and strategic situations.