Copyright © 2011 Sun Shin Ahn and Young Hee Kim. This is an open access article distributed under the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The notion of a -semigroup is introduced, and related properties are investigated. The concept of left (resp., right)
deductive systems of a -semigroup is also introduced.