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Creators/Authors contains: "Okun, Boris"

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  1. ; ; (, Mathematische Annalen)
    We show that Gromov–Thurston branched covers satisfy the Singer conjecture whenever the degree of the cover is not divisible by a finite set of primes determined by the base manifold and the branch locus. 
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    Free, publicly-accessible full text available April 4, 2026
  2. ; (, Groups, Geometry, and Dynamics)
    In 2018, Kielak gave a virtual fibering criterion for RFRS groups. In this paper, we present a simpler proof of this. 
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    Free, publicly-accessible full text available February 24, 2026
  3. ; (, Duke)
    Hain, Richard (Ed.)
    Suppose a residually finite group G acts cocompactly on a contractible complex with strict fundamental domain Q, where the stabilizers are either trivial or have normal Z-subgroups. Let dQ be the subcomplex of Q with nontrivial stabilizers. Our main result is a computation of the homology torsion growth of a chain of finite index normal subgroups of G. We show that independent of the chain, the normalized torsion limits to the torsion of dQ shifted a degree. Under milder assumptions of acyclicity of nontrivial stabilizers, we show similar formulas for the mod p-homology growth. We also obtain formulas for the universal and the usual L^2-torsion of G in terms of the torsion of stabilizers and topology of dQ. In particular, we get complete answers for right-angled Artin groups, which shows that they satisfy a torsion analogue of Lück’s approximation theorem. 
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    Full Text Available 
  4. ; ; (, Geometric and Functional Analysis)
    We introduce a hyperbolic reflection group trick which builds closed aspherical manifolds out of compact ones and preserves hyperbolicity, residual finiteness, and—for almost all primes p—-homology growth above the middle dimension. We use this trick, embedding theory and manifold topology to construct Gromov hyperbolic 7-manifolds that do not virtually fiber over a circle out of graph products of large finite groups 
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    Accepted Manuscript Full Text Available
  5. ; ; (, Inventiones mathematicae)
    null (Ed.)
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