Novikov–Shubin invariant

In mathematics, a Novikov–Shubin invariant. introduced by Novikov and Shubin (1986), is an invariant of a compact Riemannian manifold related to the spectrum of the Laplace operator acting on square-integrable differential forms on its universal cover. It gives a measure of the density of eigenvalues around zero. It can be computed from a triangulation of the manifold, and it is an homotopy invariant. In particular it does not depend on the chosen Riemannian metric on the manifold.

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