Young Hee Kim, Department of Mathematics, Chungbuk National University, Chongju 361-763, Korea, e-mail: firstname.lastname@example.org; Hee Sik Kim, Department of Mathematics, Hanyang University, Seoul 133-791, Korea, e-mail: email@example.com
Abstract: In this note we show that a subtraction algebra is equivalent to an implicative $BCK$-algebra, and a subtraction semigroup is a special case of a $BCI$-semigroup.
Keywords: subtraction algebra, subtraction semigroup, implicative $BCK$-algebra, $BCI$-semigroup
Classification (MSC2000): 06F35
Full text of the article: