  In a 1991 paper, Asher Peres and the author theoretically analyzed a set of
unentangled bipartite quantum states that could apparently be distinguished
better by a global measurement than by any sequence of local measurements on
the individual subsystems. The present paper returns to the same example, and
shows that the best result so far achieved can alternatively be attained by a
measurement that, while still global, is "unentangled" in the sense that the
operator associated with each measurement outcome is a tensor product.
