中文摘要：

从三支决策的视角出发，系统地介绍了三支决策与粗糙集理论相融合的理论、方法和应用．考虑到粗糙集理论中的正域、负域和边界域可分别生成相应的接受、拒绝和延迟决策规则，三支决策赋予粗糙集新的语义解释．通过分析三支决策与概率粗糙集、决策粗糙集间的关系；三支决策与二支决策、多支决策的关系；以及三支决策在扩展模型、属性约简和规则推导方法；在信息、工程、管理和医学等方面的应用，给出三支决策研究的现状．最后，指出了三支决策发展的未来方向．

英文摘要：

From the perspective of three way decisions,the theory,methodology and applications of rough sets are reinterpreted and systematically investigated. The three regions of rough sets can generate rules of acceptance, rejection and deferment, respectively, which provides a new semantic explanation of rough sets. The current researches of three-way decisions are carefully investigated via five different aspects： a）the relationship between three-way decisions and probabilistie rough sets and decision theoretic rough sets; b）the relationship between three way deeisions and two way decisions and multi way decisions; c）the extended models of three-way decisions; d）the attributes reduetion and rules acquisition of three-way decisions;e）the applications of three way decisions in different domains. Finally,we point out future researches on three-way decisions.