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Stochastic Matrix


A stochastic matrix, also called a probability matrix, probability transition matrix, transition matrix, substitution matrix, or Markov matrix, is matrix used to characterize transitions for a finite Markov chain, Elements of the matrix must be real numbers in the closed interval [0, 1].

A completely independent type of stochastic matrix is defined as a square matrix with entries in a field F such that the sum of elements in each column equals 1. There are two nonsingular 2×2 stochastic matrices over Z_2 (i.e., the integers mod 2),

 [1 0; 0 1]  and  [0 1; 1 0].

There are six nonsingular stochastic 2×2 matrices over Z_3,

 [0 1; 1 0],[0 2; 1 2],[1 0; 0 1],[1 2; 0 2],[2 0; 2 1],[2 1; 2 0].

In fact, the set S of all nonsingular stochastic n×n matrices over a field F forms a group under matrix multiplication. This group is called the stochastic group.

The following tables give the number of distinct stochastic matrices (and distinct nonsingular stochastic matrices) over Z_m for small m.

mstochastic n×n matrices over Z_m
21, 4, 64, 4096, ...
31, 9, 729, ...
41, 16, 4096, ...
mstochastic nonsingular n×n matrices over Z_m
21, 2, 24, 1440, ...
31, 6, 450, ...
41, 12, 3108, ...

See also

Doubly Stochastic Matrix, Horn's Theorem, Majorization, Markov Chain, Stochastic Group

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References

Poole, D. G. "The Stochastic Group." Amer. Math. Monthly 102, 798-801, 1995.

Referenced on Wolfram|Alpha

Stochastic Matrix

Cite this as:

Weisstein, Eric W. "Stochastic Matrix." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/StochasticMatrix.html

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