In mathematics and statistics, a probability vector or stochastic vector is a vector with non-negative entries that add up to one.
The positions (indices) of a probability vector represent the possible outcomes of a discrete random variable, and the vector gives us the probability mass function of that random variable, which is the standard way of characterizing a discrete probability distribution.
[1] Here are some examples of probability vectors.
The vectors can be either columns or rows.
Therefore, the set of stochastic vectors coincides with the standard