This paper deals with the formal system of propositional calculus of medium logic (MP).

本文讨论了中介逻辑命题演算(MP)的形式系统。

MP~M is a 3-valued logic propositional calculus system which is based on the medium logic system, and it is used to deal with the incomplete information in the database.

MP~M系统是在中介逻辑系统的基础上建立起来的，用于处理数据库中不完全信息的三值逻辑命题演算系统。