The categorical distribution, also called the generalized Bernoulli distribution or multinoulli distribution, is the discrete
distribution of a single outcome from possible categories. If category
has probability
, where
and
, then a categorically distributed random
variable
satisfies, for
,
The categorical distribution is the multinomial distribution with one trial. Equivalently, it can be represented by a vector
having exactly one component equal to 1 and all other components equal to 0. For
,
it reduces to the Bernoulli distribution
after the two categories are labeled 0 and 1.