# Definition:Continuous Real Function/Right-Continuous/Point

## Contents

## Definition

Let $S \subseteq \R$ be an open subset of the real numbers $\R$.

Let $f: S \to \R$ be a real function.

Let $x_0 \in S$.

Then $f$ is said to be **right-continuous at $x_0$** if and only if the limit from the right of $f \left({x}\right)$ as $x \to x_0$ exists and:

- $\displaystyle \lim_{\substack{x \mathop \to x_0^+ \\ x_0 \mathop \in A}} f \left({x}\right) = f \left({x_0}\right)$

where $\displaystyle \lim_{x \mathop \to x_0^+}$ is a limit from the right.

Furthermore, $f$ is said to be **right-continuous** if and only if:

- $\forall x_0 \in S$, $f$ is
**right-continuous at $x_0$**

## Also known as

A function which is **right-continuous** (either at a point or generally) is also seen referred to as **continuous from the right**.

## Also see

## Sources

- 1975: W.A. Sutherland:
*Introduction to Metric and Topological Spaces*... (previous) ... (next): $2.2$: Examples - 1977: K.G. Binmore:
*Mathematical Analysis: A Straightforward Approach*... (previous) ... (next): $\S 8.6$