Which Soviet mathematician was interrogated by the KGB as a result of his or her work, Sergei Novikov or Bella Subbotovskaya?
Bella Subbotovskaya Bella Abramovna Subbotovskaya (b. 1938 - d. 23 September 1982) was a Soviet mathematician who founded the short-lived Jewish People's University (1978–1983) in Moscow. The school's purpose was to offer free education to those affected by structured anti-Semitism within the Soviet educational system. Its existence was outside Soviet authority and it was investigated by the KGB. Subbotovskaya herself was interrogated a number of times by the KGB and shortly thereafter was hit by a truck and died, in what has been speculated was a assassination.
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 .