研究了模糊模态逻辑中的永真式与基本模态逻辑中的有效公式之间的关系.证明了永真式一定是逻辑有效公式,但反之不真;在模糊模态逻辑中,针对一类重要的二元关系、即连续型二元关系引入了准永真式的概念,研究了准永真式的基本性质,并结合£^*系统构造出了一类永真式和准永真式.
Relationship between tautologies in fuzzy modal logic and valid formulas in basic modal logic is investigated. It is proved that modal tautologies are logically valid but not vice versa;Based on a class of continuous binary relations, the concept of quasi-tautology is introduced in fuzzy modal logic, basic properties of quasi-tautologies is obtained, and a class of tautologies and quasi-tautologies are constructed by means of theorems in the logic system £^*.