R. A. Borzooei and M. Bakhshi
Some results on hyper BCK-algebras

In this paper by considering the notion of hyper BCK-algebra, we state and prove some theorems which determine the relationship among (weak) byper BCK-ideals, positive implicative hyper BCK-ideals of types 1,3, ... ,8 and hypersubalgebras, under some suitable conditions. Moreover, we define the notions of commutative hyper BCK-ideals of types 1, 2, 3 and 4 and obtain some results.