Abstract: Multiple-valued logic is the logic that has more than two values.One important problem in multiple-valued logic completeness theory is the decision of Sheffer function，which depends on deciding the minimal covering of the precomplete classes.In deep research on the Sheffer function in partial four-valued logic，the determinant algorithm of Sheffer functions in partial four-valued logic is given，which is according to the minimal covering of its precomplete classes.This algorithm can determine all Sheffer functions in partial four-valued logic.

Key words: multiple-valued logic, Sheffer functions, precomplete sets, minimal covering

摘要： 多值逻辑是指一切逻辑值的取值数大于2的逻辑。Sheffer函数的判定问题是多值逻辑完备性理论中的一个重要问题，此问题的解决依赖于定出多值逻辑函数集中所有准完备集的最小覆盖。在深入研究部分四值逻辑中Sheffer函数的基础上，根据部分四值逻辑中准完备集的最小覆盖，给出了一个部分四值逻辑中Sheffer函数的判定算法。此算法能够判定任意一个函数是不是部分四值逻辑中的Sheffer函数。

关键词: 多值逻辑, Sheffer函数, 准完备集, 最小覆盖