# Ideal point

From Encyclopedia of Mathematics

*improper point, point at infinity, infinitely-distant point*

A point that completes the plane in order to describe certain geometrical relations and systems. For example, an inversion is a one-to-one mapping of the Euclidean plane completed by an ideal point; completion of the affine plane by ideal points leads to the concept of a projective plane. See also Infinitely-distant elements.

**How to Cite This Entry:**

Ideal point.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Ideal_point&oldid=34379

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