Given two disjoint groups X and Y, each containing n people. Suppose an experiment (or a game) requires all pairwise comparisons between x∈X and y∈Y, and only one comparison can be done at a time. The paper deals with sequential orderings of all pairs (x,y)∈X×Y for which the maximum time duration a person has to stay in the sequence for comparison purposes or the total time duration of all people in the sequence, respectively, is small. The analogous problem of finding optimal sequences of all k-subsets of a given set was considered in 1977 by Hwang and Lagarias.
