Neutral vector
MULTIVARIATE RANDOM VARIABLE THAT EXHIBITS A PARTICULAR TYPE OF STATISTICAL INDEPENDENCE
In statistics, and specifically in the study of the Dirichlet distribution, a neutral vector of random variables is one that exhibits a particular type of statistical independence amongst its elements. In particular, when elements of the random vector must add up to certain sum, then an element in the vector is neutral with respect to the others if the distribution of the vector created by expressing the remaining elements as proportions of their total is independent of the element that was omitted.