MONOTONICITY OF SINGLE-SEAT PREFERENTIAL ELECTION RULES

Various properties of preferential election rules are described, inclu ding nine forms of monotonicity. It is shown that Condorcet's principl e is incompatible with many of them. Some progress is made towards the task of determining all maximal mutually compatible subsets of these properties. To that end, a survey is given of the monotonicity propert ies of many known single-seat preferential election rules, and four ne w rules are described, including one that is offered as a more monoton ic practical alternative to the Alternative Vote.