Kyoung Ja Lee and Young Bae Jun Hannam University, Gyeongsang National University
Abstract : Using ${\mathcal N}$-structures, the notion of an ${\mathcal N}$-essence in a subtraction algebra is introduced, and related properties are investigated. Relations among an ${\mathcal N}$-ideal, an ${\mathcal N}$-subalgebra and an ${\mathcal N}$-essence are investigated.
