It is shown that a social choice rule f : X^N ? X as defined on a bounded distributive lattice (X, ) is strategy-proof on the set of all profiles of unimodal total preorders on X if and only if it can be represented as an iterated median of projections and constants. The equivalence of individual...

A voting protocol is said to be strongly β-participatory if for any voter i and any strategy profile either the outcome is i′s preferred one or i has a sincere strategy which would ensure her a better outcome, and VNM-strategy-proof if at any preference profile the set of sincere strategies...

A choice function is (weakly) width-maximizing if there exists a dissimilarity- i.e. an irreflexive symmetric binary relation- on the underlying object set such that the choice sets are (include, respectively) dissimilarity chains of locally maximum size. Width-maximizing and weakly...

It is shown that simple and coalitional strategy-proofness of a voting rule as defi?ned on the full unimodal domain of a convex idempotent interval space (X; I) are equivalent properties if (X; I) satis?es interval anti-exchange, a basic property also shared by a large class of convex geometries...

It is shown that a two-valued and nonsovereign voting rule is strategy-proof on any preference domain that includes all pro?les of total preorders with a unique maximum if and only if votes for noneligible feasible alternatives are only available to dummy voters. It follows that dummy-free...