The second part of the thesis is about the application of credibility theory. We employ credibility theory to study portfolio selection problem, and build three types of portfolio selection models in fuzzy environment.

• 论文第二部分是可信性理论的应用:将可信性理论应用于有价证券选择问题,通过模糊变量的期望值和方差,以及可信性测度建立了三类模糊环境下的有价证券选择模型。