Question: Which Soviet mathematician was interrogated by the KGB as a result of his or her work, Sergei Novikov or Bella Subbotovskaya?

Context articles: Wess–Zumino–Witten model
Sergei Novikov (mathematician)
Novikov's compact leaf theorem
Independent University of Moscow
Anton Zorich
Novikov conjecture
Bella Subbotovskaya
William Browder (mathematician)
Normal invariant
Circle-valued Morse theory

In theoretical physics and mathematics, a Wess–Zumino–Witten (WZW) model, also called a Wess–Zumino–Novikov–Witten model, is a type of two-dimensional conformal field theory named after Julius Wess, Bruno Zumino, Sergei Novikov and Edward Witten.
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.
In mathematics, Novikov's compact leaf theorem, named after Sergei Novikov, states that
The Independent University of Moscow (IUM) (Russian: Независимый Московский Университет (НМУ) ) is a small educational organisation with rather informal status located in Moscow, Russia.
 It was founded in 1991 by a group of prominent Russian mathematicians that included Vladimir Arnold (chairman) and Sergei Novikov.
 The IUM consists of the departments of mathematics and theoretical physics and the post-graduate school.
 Anyone can attend lectures and seminars and become a student after passing three exams.
 The IUM is the only non-state college for the preparation of professional mathematicians in Russia .
 An IUM diploma is recognized by such authoritative mathematical institutions as the Steklov Institute of Mathematics, Harvard University and the Weizmann Institute.
Anton V. Zorich (in Russian: "Антон Владимирович Зорич"; born 3 September 1962) is a Russian mathematician at the "Institut Mathématiques de Jussieu".
 He received his Ph.D. from Moscow State University under the supervision of Sergei Novikov.
The Novikov conjecture is one of the most important unsolved problems in topology.
 It is named for Sergei Novikov who originally posed the conjecture in 1965.
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.
William Browder (born January 6, 1934) is an American mathematician, specializing in algebraic topology, differential topology and differential geometry.
 Browder was one of the pioneers with Sergei Novikov, Dennis Sullivan and Terry Wall of the surgery theory method for classifying high-dimensional manifolds.
In mathematics, a normal map is a concept in geometric topology due to William Browder which is of fundamental importance in surgery theory.
 Given a Poincaré complex "X" (more geometrically a Poincaré space), a normal map on "X" endows the space, roughly speaking, with some of the homotopy-theoretic global structure of a closed manifold.
 In particular, "X" has a good candidate for a stable normal bundle and a Thom collapse map, which is equivalent to there being a map from a manifold "M" to "X" matching the fundamental classes and preserving normal bundle information.
 If the dimension of "X" is formula_1 5 there is then only the algebraic topology surgery obstruction due to C. T. C. Wall to "X" actually being homotopy equivalent to a closed manifold.
 Normal maps also apply to the study of the uniqueness of manifold structures within a homotopy type, which was pioneered by Sergei Novikov.
In mathematics, circle-valued Morse theory studies the topology of a smooth manifold by analyzing the critical points of smooth maps from the manifold to the circle, in the framework of Morse homology.
 It is an important special case of Sergei Novikov's Morse theory of closed one-forms.