ABSTRACT
With sets {a1, a2, . . . , aq} and {b1, b2, . . . , bs} containing q and s distinct items, respectively, it is possible to form qs distinct pairs (or 2-tuples) of the form (ai, bj), i = 1, 2, . . . , q and j = 1, 2, . . . , s. Adding a third set {c1, c2, . . . , ct} containing t distinct items, it is possible to form qst distinct triplets (or 3-tuples) of the form (ai, bj , ck), i = 1, 2, . . . , q, j = 1, 2, . . . , s, and k = 1, 2, . . . , t. Extensions to more than three sets of distinct items are straightforward.
