<正>The present age is an informational one. Treating the information has become an important step for people to make quantitative analysis in ordinary life, production, scientific study, etc. People have already obtained rich experience and knowledge about treating certain information. And this is just called classical mathematics. In order to represent and treat uncertain information (random information, fuzzy information, grey information and unascertained information), uncertain mathematics has appeared correspondingly (probability statistics, fuzzy math ematics, grey mathematics and unascertained mathematics). Probability statistics[1], fuzzy mathematic[2], grey mathematics[3] and unascertained mathematics[4] are used