Communications of the
Korean Mathematical Society CKMS

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.

Keywords: subtraction algebra, ${\mathcal N}$-subalgebra, ${\mathcal N}$-ideal, ${\mathcal N}$-essence

MSC numbers: 06F35, 03G25