1·With respect to the principal disjunctive normal form and the principal conjunctive normal form, we also approach the properties of the subscript sets derived from the minimum term and maximum term.
讨论了命题公式的主析取范式、主合取范式中的极小项与极大项下标集合的性质，利用主范式的下标集合得到了命题公式蕴涵的几个充要条件。
2·Aiming at the problem of equivalent conversion from conjunctive normal form to disjunctive normal form, an effective algorithm was proposed to construct reduction tree based on discernibility matrix.
针对差别矩阵求约简过程中合取范式向析取范式等价转换的难题，提出一种基于差别矩阵构造约简树的有效方法。
3·Firstly, a classification-tree is constructed based on specification of the test object, and then test cases obtained from the classification-tree are refined by generating a disjunctive normal form.
由软件的形式规格说明构造分类树，再把由分类树方法得到的测试用例转化为析取范式，进一步精炼测试用例。