A necessary and sufficient condition for dominant strategy implementability when preferences are quasilinear is that, for any individual i and any choice of the types of the other individuals, all k-cycles in i's allocation graph have nonnegative length for every integer k � 2. Saks and Yu...

We study the question of which social choice functions from an abstract type space to a set of outcomes are truthful, i.e., implementable by truthful mechanisms, when utilities are quasi-linear. For convex domains, our main theorem characterizes truthful social choice functions as those...