摘要 以前述类方概念研究为基础，结合目前方剂相似度研究的不足，分析了类方衍化关系自动发现的难点。然后，对类方衍化关系的内涵进行了剖析，提出其应包含变化、制方时间、药物组成和相似度等多方面的特征和因素。最后，对中药、方剂等概念和关系进行形式化定义的基础上，完成了类方衍化关系的形式化表达，为后续类方衍化关系的判别模型的构建奠定了基础。

    关键词 类方；类方衍化关系；形式化表达

    Abstract Following the previous research on analogous formulae，this paper analyzes the difficulties to automatically discover the analogous formulae derivation relationship (AFDR) based on the review of current formulae similarity models.Furthermore，the paper carries on thorough analysis on connotation of AFDR and suggests it should comprise of many features and factors such as transformation ......