1 entry tagged fairness, newest first.
Five towns share a council in proportion to their populations, and the fairest-looking rule there is — give every town the whole part of its quota, then hand the leftovers to the largest fractions — takes a seat away from a town three times as the council grows from five seats to sixty, at 29, 34 and 51, with nobody moving house. Seven people split 3, 3, 1 is the smallest population that can do it, and two towns can never do it at all. Hold the council still and let the people move instead and it fails the other way round: nine people becoming thirteen is enough for a town that gains somebody to lose a seat to a town that gains nobody. The rules that cannot do either buy that by handing a town more seats than its quota allows — Balinski and Young proved in 1982 that you have to give up one or the other.