Exponential map

This page is about the exponential map in differential geometry. For discrete dynamical systems, see Exponential map (discrete dynamical systems).

In differential geometry, the exponential map is a generalization of the ordinary exponential function of mathematical analysis. Important special cases include:

• exponential map (Riemannian geometry) for a manifold with a Riemannian metric,
• exponential map (Lie theory) from a Lie algebra to a Lie group,
• More generally, in a manifold with an affine connection, $X\mapsto {\gamma }_X(1)$, where ${\gamma }_X$ is a geodesic with initial velocity X, is sometimes also called the exponential map. The above two are special cases of this with respect to appropriate affine connections.
• Euler's formula forming the unit circle in the complex plane.

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