Fuzzy Subalgebras in BCK/BCI-Algebras

In this paper, the notion of not quasi-coincidence ?? of a fuzzy point with a fuzzy set is considered. We introduce the notion of ?,??qk -fuzzy ( ?,qk -fuzzy) subalgebra in a BCK/BCI-algebra X and several properties are investigated. Specially, we show that under certain conditions an ?,??qk -fuzzy subalgebra can be expressed such that consist of a union of two proper non-equivalent ?,??qk -fuzzy subalgebras.