  Consider the Quadratic Assignment Problem (QAP): given two matrices A and D,
minimize {trace AXDX^T: X is a permutation matrix}. New lower bounds were
obtained recently (Mittelmann and peng [8]) for the QAP where D is either the
Manhattan distance matrix of a rectangular grid, or the Hamming distance of a
hypercube. In this note, we show that the results in [8,11] extend to the case
where D is a spherical Euclidean distance matrix, which includes the Manhattan
distance matrix and the Hamming distance matrix as special cases.

Optimization and Control