# Half-line (ray)

From Encyclopedia of Mathematics

One of the parts of a line into which that line is divided by any point $O$ on it. If the point $O$ is attached to the half-line, then that half-line is called a closed half-line (or closed ray).

**How to Cite This Entry:**

Half-line (ray).

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Half-line_(ray)&oldid=31426

This article was adapted from an original article by BSE-3 (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article