Which Soviet mathematician was interrogated by the KGB as a result of his or her work, Sergei Novikov or Bella Subbotovskaya?
Sergei Novikov (mathematician) Sergei Petrovich Novikov (also Serguei) (Russian: Серге́й Петро́вич Но́виков) (born 20 March 1938) is a Soviet and Russian mathematician, noted for work in both algebraic topology and soliton theory. In 1970, he won the Fields Medal.
Novikov–Shubin invariant In mathematics, a Novikov–Shubin invariant. introduced by , 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 .