Definition:Independent Random Variables/Discrete/Pairwise Independent

Definition
Let $\EE$ be an experiment with probability space $\struct {\Omega, \Sigma, \Pr}$. Let $X = \tuple {X_1, X_1, \ldots, X_n}$ be an ordered tuple of random variables.

Then $X$ is pairwise independent $X_i$ and $X_j$ are independent (of each other) whenever $i \ne j$.