中文摘要：

在供应商向多个零售商提供贸易信贷的环境下，本文考虑了零售商存在违约风险和他们之间存在竞争时的供应链协调问题。研究表明，在比例分配市场需求下，多个竞争的零售商之间存在唯一的纳什均衡订购量，以及零售商违约风险的提高和他们之间竞争增强都会增加均衡订购量。当零售商之间的竞争较弱时，贸易信贷将无法协调供应链。为此，本文使用了收益分享与贸易信贷相结合的机制以协调供应链，且分析了零售商的违约风险和他们之间的竞争对协调契约参数的影响。当零售商的竞争强度一定时，批发价和风险溢价都随着零售商违约风险的提高而增大，而收益分享比例随着违约风险的提高而减小；当零售商的违约风险一定时，批发价和风险溢价都随着零售商之间竞争强度的提高而增大，而收益分享比例随着竞争强度的增强而减小。进一步的研究发现，零售商的违约风险越高以及他们之间竞争越激烈对零售商越不利，而对供应商越有利。最后，结合数值实验验证了收益共享-贸易信贷契约的有效性。

英文摘要：

We consider a supply chain with a supplier and multiple competing retailers. We explore the issue of supply chain coordination by considering trade credit, its risk and competition among retailers. It shows that when allocating demand among the retailers proportional to their order quantities, there exists a unique Nash equilibrium order quantity which increases in default risk and the number of retailers respectively; and trade credit fails to coordinate the supply chain when competition is weak. In order to coordinate the supply chain, we assume that supplier grants trade credit and revenue sharing. Then, we analytically examine the impacts of retail- er＇s default risk and competition among retailers on coordinating contract parameters. Our results show that supplier＇ s wholesale price and risk premium increase in default, but the revenue-sharing ratio that is allocated to retailers decreases in it; supplier＇ s wholesale price and risk premium increase in the number of retailers, but the revenue - sharing ratio decreases in it. Further more, we show that when the retailers＇ default risk is higher and the competition among retailers is more intensive, it is worse to the retailers but is better to the supplier. Finally, we demonstrate the theoretical results of the proposed model through a numerical example.