Envy-free division of discrete cakes

Abstract

Abstract We address the problem of existence of an envy-free distribution of pieces among two or more players in the cake-cutting setting with the minimum number of cuts. Our cakes are discrete in the sense that the playersʼ valuations are concentrated on atoms. These atoms are placed on an interval and no two players give positive value to atoms placed at the same position. We prove the existence of an envy-free allocation for any discrete cake and any number of players by resorting to Spernerʼs Lemma, a suitable triangulation, and moving-knife arguments. Our results also apply to pies, which are defined over circumferences instead of intervals.