Reflection (mathematics)

Mapping from a Euclidean space to itself

In mathematics, a reflection (also spelled reflexion) is a mapping from a Euclidean space to itself that is an isometry with a hyperplane as the set of fixed points; this set is called the axis (in dimension 2) or plane (in dimension 3) of reflection. The image of a figure by a reflection is its mirror image in the axis or plane of reflection. For example, the mirror image of the small Latin letter p for a reflection with respect to a vertical axis (a vertical reflection) would look like q.

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