I organize the Midrasha.
The Midrasha takes place in Weizmann on Mondays in two sessions:
Morning session (11:15–13:00, Goldsmith Rm 108) – learning seminar,
Afternoon session (14:15–16:00, Goldsmith Rm 108) – research seminar.
Check out the Midrasha's website for more details!
Finite Approximations of Groups: Sofic, MF, and Hyperlinear Groups
Following OpenAI’s dramatic solution to the longstanding sofic-group problem and the remarkable developments that followed almost immediately, we decided to devote (at least) this semester’s learning seminar to studying finite approximations of groups.
First meeting: October 19, 2026.
Main Reference
[Plan] Seminar plan with references, generated by humans, 2026.
Topics and Speakers
The topics and speakers for each week are here.
Superrigidity
First meeting: April 13, 2026.
Main Reference
[Houd] Cyril Houdayer, Superrigidity. Lecture notes, 2023.
Hilbert's Fifth Problem
First meeting: October 27, 2025.
Main Reference
[Tao] Terence Tao, Hilbert's fifth problem and related topics. Graduate Studies in Mathematics, 153. American Mathematical Society, Providence, RI, 2014.
Discrete Groups, Expanding Graphs, and Measure Invariants
First meeting: March 24, 2024.
Main Reference
[Lub] Alexander Lubotzky, Discrete Groups, Expanding Graphs and Invariant Measures. With an appendix by Jonathan D. Rogawski. Progress in Mathematics, 125. Birkhäuser Verlag, Basel, 1994.
Measured Group Theory
First meeting: November 4, 2024.
Main References
[Fur] Furman, A survey of the measured group. Geometry, rigidity, and group actions, 296–374, 2011.
[Kerr-Li] Kerr and Li, Ergodic Theory: Independence and Dichotomies. Springer Monographs in Mathematics. Springer, Cham, 2016.
Secondary References
[Ioa] Ioana, Orbit equivalence of ergodic group actions (lecture notes).
[Loh] Löh, Ergodic Theory of Groups (lecture notes), 2020.
Expanders, Ramanujan Graphs, Property Testing, Stability, and Group Approximation
First meeting: April 8, 2024.
The Spectrum of Hyperbolic Surfaces
First meeting: December 11, 2023.
Main reference: Bergeron. The spectrum of hyperbolic surfaces. Translated from the 2011 French original by Brumley. Universitext. Springer, 2016.
Coxeter Groups and Buildings
First meeting: October 30, 2023.
Main reference: Thomas. Geometric and topological aspects of Coxeter groups and buildings. Lecture Notes, 2016.
Hyperoblic Geometry
Main reference: Benedetti and Petronio. Lectures on hyperbolic geometry. Universitext. Springer-Verlag, Berlin, 1992
Harmonic Analysis
Main reference: Folland. A course in abstract harmonic analysis. Second edition. Textbooks in Mathematics. CRC Press, Boca Raton, FL, 2016.