Definition:Neumann Eigenvalue
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Definition
Let $\struct {M, g}$ be a compact connected Riemannian manifold with non-empty boundary $\partial M$.
Let $u \in \map {C^\infty} M : M \to \R$ be a smooth mapping on $M$ not identically equal to zero.
Let $\nabla^2$ be the Laplace-Beltrami operator.
Let $\lambda \in \R$ be a real number.
Let $N$ be the outward-pointing unit normal vector field on $\partial M$.
Suppose:
- $\ds \nabla^2 u + \lambda u = 0$
- $\bigvalueat {N u} {\partial M} = 0$
Then $\lambda$ is called a Neumann eigenvalue of $M$.
Source of Name
This entry was named for Carl Gottfried Neumann.
Sources
- 2018: John M. Lee: Introduction to Riemannian Manifolds (2nd ed.) ... (previous) ... (next): $\S 2$: Riemannian Metrics. Problems