How Do You Reduce a Matrix in Game Theory?


Vincent White

When it comes to game theory, matrices play a crucial role in analyzing and solving games. A matrix is a table of numbers that represents the payoffs for each player in every possible combination of strategies.

However, often these matrices can be large and complex, making it difficult to interpret and analyze them. This is where matrix reduction comes into play.

What is Matrix Reduction?

Matrix reduction is the process of simplifying a matrix without changing the game’s essential features or solutions. It involves using various mathematical operations to transform the original matrix into an equivalent but simpler form.

Why Reduce a Matrix?

Reducing a matrix has many benefits. It helps to identify the dominant strategies, which are those that provide the best outcome for a player regardless of their opponent’s strategy. Furthermore, it simplifies the analysis and makes it easier to find a Nash equilibrium, which is a state where neither player has an incentive to change their strategy.

How Do You Reduce a Matrix?

There are several methods for reducing matrices in game theory. Let’s take a look at some of them.


One way to simplify a matrix is by eliminating dominated strategies. A dominated strategy is one that always leads to worse outcomes than another strategy, regardless of what the other player does.

To eliminate dominated strategies, we compare each row and column in the matrix and eliminate any that are strictly dominated by others. In other words, if there exists another row or column that always provides equal or better payoffs regardless of what the opponent chooses, we can remove the dominated row or column without changing the solution.


Another method for reducing matrices is by using equivalence transformations. These transformations involve adding or subtracting multiples of rows or columns from each other without changing the essence of the game.

For example, if we have two rows with identical payoffs, we can subtract one from the other to create a row of zeros. This transformation does not change the solution of the game but simplifies the matrix by reducing the number of rows.

Scalar Multiplication

Scalar multiplication involves multiplying each element in a row or column by a constant. This operation does not change the essence of the game and can simplify the matrix by reducing large numbers.

Row and Column Operations

Finally, we can use various row and column operations to simplify matrices. These operations include swapping two rows or columns, adding or subtracting multiples of one row or column from another, and multiplying rows or columns by -1.

These operations help to simplify matrices by reducing their size and making them easier to analyze.


Matrix reduction is an essential tool in game theory that helps to simplify complex matrices and identify dominant strategies. By using various mathematical operations such as dominance, equivalence, scalar multiplication, and row and column operations, we can transform a large matrix into an equivalent but simpler form without changing the essence of the game.