# What Is a Matrix Game in Game Theory?

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Diego Sanchez

Game theory is a branch of mathematics that studies decision-making in situations where multiple parties are involved. One of the tools used in game theory is the matrix game, which is a simple and intuitive way to represent strategic interactions between two or more players.

What is a Matrix Game?

A matrix game is a type of game that is represented by a matrix, hence the name. In this game, each player has a set of possible actions they can take, and each combination of actions leads to a certain outcome or payoff. The matrix represents these payoffs for each player for every possible combination of actions.

Example:

Consider the following scenario: Alice and Bob are both bidding for an item at an auction. Alice can either bid \$100 or not bid at all, and Bob can either bid \$50 or not bid at all. The payoffs are as follows:

– If both Alice and Bob bid, then Alice gets the item and pays \$100 while Bob gets nothing. – If only Alice bids, then she gets the item and pays \$100.

– If only Bob bids, then he gets the item and pays \$50. – If neither bids, then nobody gets the item.

The matrix representing this game would look like this:

Bob Bids Bob Does Not Bid
Alice Bids (Item: Alice pays \$100, Bob gets nothing) (Item: Nobody wins)
Alice Does Not Bid (Item: Bob pays \$50, Bob wins) (Item: Nobody wins)

This matrix shows the payoffs for each player for every possible combination of actions.

How to Play a Matrix Game?

To play a matrix game, each player chooses their preferred strategy based on the payoffs in the matrix. For example, in the auction scenario, Alice might choose to bid if she thinks Bob will not bid, or if she values the item more than \$100. Bob might choose to bid if he thinks Alice will not bid, or if he values the item more than \$50.

Once both players have chosen their strategies, the payoffs are determined based on the corresponding cell in the matrix. For example, if Alice bids and Bob does not bid, then Alice gets the item and pays \$100 while Bob gets nothing.

Applications of Matrix Games

Matrix games are used in various fields such as economics, political science, and biology to model strategic interactions between agents. One common application is in business competition where companies have to decide on pricing and marketing strategies to outcompete their rivals.

Consider two companies that sell soda: Coca-Cola and Pepsi. They can either advertise heavily or advertise sparingly, and they can either price their products high or low. The payoffs are as follows:

– If both companies advertise heavily and price high, then they split the market equally. – If both companies advertise sparingly and price low, then they split the market equally.

– If one company advertises heavily while the other advertises sparingly and they price high respectively (i.e., Coke advertises heavily and prices high while Pepsi advertises sparingly but prices high), then Coke gets 70% of the market share while Pepsi gets 30%. – If one company advertises heavily while the other advertises sparingly and they price low respectively (i., Coke advertises heavily but prices low while Pepsi advertises sparingly and prices low), then Coke gets 30% of the market share while Pepsi gets 70%.