TY - JOUR AU - Laysirikul, Ekkachai AU - Sripon, Kitsanachai PY - 2017 TI - A Noncommutative Semigroup which Contains the Natural Numbers under Addition and Its Left Ideals JF - Naresuan University Journal: Science and Technology (NUJST); Vol 25 No 2 (2017): April - June 2017 KW - Semigroup, Subsemigroup, Left ideal, Right ideal, Isomorphism N2 -      In this paper, we introduce a new semigroup which is not commutative. Then we investigate some properties in this structure. We discover that this semigroup has no a proper right ideal. After that we find some subsemigroups of this semigroup which are left ideals. Finally, we prove that the natural numbers under addition can be embedded into this semigroup. Keyword: Semigroup, Subsemigroup, Left ideal, Right ideal, Isomorphism UR - https://www.journal.nu.ac.th/NUJST/article/view/1778