# Definition:Real Interval/Definition 2

## Definition

A **real interval** is a subset of $\R$ that is one of the following real interval types:

- closed bounded interval
- open bounded interval
- left half-open bounded interval
- right half-open bounded interval
- closed and bounded on the right
- open and bounded on the right
- closed and bounded on the left
- open and bounded on the left
- unbounded interval without endpoints

## Also see

## Sources

- 1975: W.A. Sutherland:
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