University of Mohaghegh Ardabili Journal of Hyperstructures 2251-8436 5 2 2016 12 01 Fundamental pseudo BCK-algebras 93 107 2671 10.22098/jhs.2016.2671 EN Habib Harizavi Department of Mathematics, Shahid Chamran University of Ahvaz, P.O.Box 61357- 83151, Ahvaz, Iran Rajab Ali Borzooei Department of Mathematics, Shahid Beheshti University, P.O.Box 1983969411, Tehran, Iran Taiybeh Koochakpoor Department of Mathematics, Payame Noor University of Tehran, P.O.Box 1659639884,Tehran, Iran Journal Article 2016 03 22 In this paper, we de ne the relations   and   on hyper pseudo BCK-algebras and investigate some related properties. We give a necessary and sucient condition for   to be regular. By us- ing  , we make the quotient hyper pseudo BCK-algebra. Finally, by applying the concept of fundamental on pseudo BCK-algebra, we prove that any pseudo BCK-algebra is fundamental. https://jhs.uma.ac.ir/article_2671_a2b640712325f5e3fa5392d898019adb.pdf