The definition of product about fuzzy comprehensive evaluation methods based on closeness

Closeness degree is classed on the basis of analyzing various definitions for closeness degree. At the same time,the relationship of two species definition for symmetric closeness degree is proved;the inherent connection between selection nearness principle and maximum subordination principle is discussed. Then,two kinds of non-symmetric closeness degree are constructed,its characters are proved,and the corresponding algorithms are given too. This solves problem about evaluation partly when maximum subordination principle is ineffective.