Semigroup with two elements

A semigroup is an algebraic structure consisting of a set equipped with an associative binary operation. Specifically, a set \( S \) with a binary operation \( * \) is a semigroup if it satisfies two conditions: 1. **Closure**: For any \( a, b \in S \), the result of the operation \( a * b \) is also in \( S \).