(1) The direct product (equation omitted) $E_{I}$ of BCK-algebras $E_{I}$, (i=1, 2, 3, …, n), is a BCK-algebra. (2) Let E be a BCK-algebra and $A_1$, $A_1$, …, $A_{n}$ ideals of E. Define a mapping (equation omitted) by the rule f($chi$)=( $A_1$$chi$, $A_2$$chi$, …, $A_{n}$$chi$). Then f is a homomorphism.ism.ism.