Tsachik Gelander () is an Israeli mathematician working in the fields of

Lie groups In mathematics, a Lie group (pronounced ) is a group that is also a differentiable manifold, such that group multiplication and taking inverses are both differentiable. A manifold is a space that locally resembles Euclidean space, whereas ...

topological groups In mathematics, topological groups are the combination of groups and topological spaces, i.e. they are groups and topological spaces at the same time, such that the continuity condition for the group operations connects these two structures t ...

symmetric spaces In mathematics, a symmetric space is a Riemannian manifold (or more generally, a pseudo-Riemannian manifold) whose group of isometries contains an inversion symmetry about every point. This can be studied with the tools of Riemannian geometr ...

, lattices and discrete subgroups (of Lie groups as well as general locally compact groups). He is a professor in

Northwestern University Northwestern University (NU) is a Private university, private research university in Evanston, Illinois, United States. Established in 1851 to serve the historic Northwest Territory, it is the oldest University charter, chartered university in ...

. Gelander earned his PhD from the

Hebrew University of Jerusalem The Hebrew University of Jerusalem (HUJI; ) is an Israeli public university, public research university based in Jerusalem. Co-founded by Albert Einstein and Chaim Weizmann in July 1918, the public university officially opened on 1 April 1925. ...

in 2003, under the supervision of

Shahar Mozes Shahar Mozes () is an Israeli mathematician. Mozes received in 1991, his doctorate from the Hebrew University of Jerusalem with thesis ''Actions of Cartan subgroups'' under the supervision of Hillel Fürstenberg. (doctoral dissertation) At the H ...

. His

doctoral dissertation A thesis (: theses), or dissertation (abbreviated diss.), is a document submitted in support of candidature for an academic degree or professional qualification presenting the author's research and findings.International Standard ISO 7144: D ...

, ''Counting Manifolds and Tits Alternative'', won the Haim Nessyahu Prize in Mathematics, awarded by the

Israel Mathematical Union The Israel Mathematical Union (IMU) () is an association of professional mathematicians in Israel. It is a member of the European Mathematical Society and the International Council for Industrial and Applied Mathematics, and has reciprocity memb ...

for the best annual doctoral dissertations in mathematics. After holding a Gibbs Assistant Professorship at Yale University, and faculty positions at the Hebrew University of Jerusalem and the Weizmann Institute of Science, Gelander joined Northwestern where he is currently a professor of mathematics. He contributed to the theory of lattices, Fuchsian groups and

local rigidity Local rigidity theorems in the theory of discrete subgroups of Lie groups are results which show that small deformations of certain such subgroups are always trivial. It is different from Mostow rigidity and weaker (but holds more frequently) than ...

, and the work on Chern's conjecture and the Derivation Problem. Among his well-known results is the solution to the Goldman conjecture, i.e. that the action of

Out(F_n)

on the deformation variety of a compact Lie group is ergodic when

n

is at least

3

. He gave the distinguished Nachdiplom Lectures at ETH Zurich in 2011, and was an invited speaker at the 2018

International Congress of Mathematicians The International Congress of Mathematicians (ICM) is the largest conference for the topic of mathematics. It meets once every four years, hosted by the International Mathematical Union (IMU). The Fields Medals, the IMU Abacus Medal (known before ...

, giving a talk under the title of ''Asymptotic Invariants of Locally Symmetric Spaces.'' He was one of the recipients of the first call of the European Research Council (ERC) Starting Grant (2007), and in 2021 he won the ERC Advanced Grant.ERC Advanced Grants 2021 - List of Principal Investigators
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Selected publications

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References

{{Authority control Hebrew University of Jerusalem alumni Israeli mathematicians Living people Mathematics journal editors Year of birth missing (living people)