Complete Convergence for Negatively Dependent Sequences of Random Variables

for all x, y ∈ R. Moreover, it follows that 1.2 implies 1.1 , and hence, 1.1 and 1.2 are equivalent. Ebrahimi and Ghosh 1 showed that 1.1 and 1.2 are not equivalent for a collection of 3 or more random variables. They considered random variables X1, X2, and X3 where X1, X2, X3 assumed the values 0, 1, 1 , 1, 0, 1 , 1, 1, 0 , and 0, 0, 0 each with probability 1/4. The random variables X1, X2, and X3 are pairwise independent, and hence, they satisfy both 1.1 and 1.2 for all pairs. However,