The division problem consists of allocating an amount of a perfectly divisi
ble good among a group of n agents. Sprumont (1991) showed that if agents h
ave single-peaked preferences over their shares, then the uniform allocatio
n rule is the unique strategy-proof, efficient, and anonymous rule. We iden
tify the maximal set of preferences, containing the set of single-peaked pr
eferences, under which there exists at least one rule satisfying the proper
ties of strategy-proofness, efficiency, and strong symmetry. In addition, w
e show that our characterization implies a slightly weaker version of Ching
and Serizawa's (1998) result. (C) 2001 Academic Press.