Definition:Real Interval/Singleton

Definition
Let $a, b \in \R$.

Consider the closed interval $\left [{a \,.\,.\, b} \right] \subseteq \R$.

When $a = b$:


 * $\left [{a \,.\,.\, b} \right] = \left [{a \,.\,.\, a} \right] = \left\{{x \in \R: a \le x \le a}\right\} = \left\{{a}\right\}$

Such an interval is sometimes referred to as a singleton interval.