中文摘要：

以网络零售商入驻多个电商平台开设网店为背景，在库存独立、单向关联和统一管理库存三种库存策略下，分别研究了网络零售商协调多个网店的动态定价决策和电商平台的动态促销决策，建立了网络零售商和电商平台的动态规划方程，并给出了求解最优定价和最优促销决策的方法。研究表明电商平台的促销活动可以提高零售商和电商平台的期望利润，零售商通过承担部分促销成本可以进一步提高双方的期望利润。另外，零售商的库存持有成本不仅会影响网店的初始库存，还会影响库存策略的选择。

英文摘要：

Based on an online retailer which set up multi online stores in E-commerce sites, this paper develops a model of dynamic programming to study online retailer＇s dynamic pricing policy and E-commerce sites＇ dynamic promotion policy under three inventory patterns which include independent inventory, half-independent inventory and unified inventory. It is found that E-commerce sites＇ promotional efforts lead to a higher expected profit for online retailer and E- commerce sites＇ which will be more higher if online retailer shares part of the promotion cost. Furthermore, holding cost of retailer influences not only the beginning inventory of two online stores,but also the selecting of inventory patterns. Key words： joint promotion contact; dynamic promotion; dynamic pricing; online retailer