Monoid Ideal

A subset $I\subseteq M$ of a Monoid $M$ is a

• Left ideal if for all $xi:X$, $i\in I\Rightarrow xi\in I$
• Right ideal if for all $ix:X$, $i\in I\Rightarrow ix\in I$
• Two-sided ideal if it is both a left and right ideal.

Properties