This page list all events and seminars that take place in the department this week. Please use the form below to choose a different week or date range.


Order and disorder in multiscale substitution tilings

Nov 9, 14:30—15:30, 2021, Math -101


Yotam Smilansky (Rutgers University)


The study of aperiodic order and mathematical models of quasicrystals is concerned with ways in which disordered structures can nevertheless manifest aspects of order. In the talk I will describe examples such as the aperiodic Penrose and pinwheel tilings, together with several geometric, functional, dynamical and spectral properties that enable us to measure how far such constructions are from demonstrating lattice-like behavior. A particular focus will be given to new results on multiscale substitution tilings, a class of tilings that was recently introduced jointly with Yaar Solomon.

אשנב למתמטיקה

כאשר (כמעט) כל האיברים של חבורה נראים אותו הדבר Online

Nov 9, 18:10—19:30, 2021, בניין 32 חדר 309 וכן במרשתת


יאיר גלזנר


בחבורות טופולוגיות רבות מתגלה תופעה מפתיעה: יש מחלקת צמידות אחת הרבה יותר גדולה מכל השאר (למשל במובן משפט הקטגוריה של בייר). נראה שלתופעה זו יש מסקנות אלגבריות חזקות ומפתיעות.


Rational points on ramified covers of abelian varieties, online lecture

Nov 10, 16:00—17:15, 2021, -101


Ariyan Javanpeykar (Meinz)


Let X be a ramified cover of an abelian variety A over a number field k. According to Lang’s conjecture, the k-rational points of X should not be dense. In joint work with Corvaja, Demeio, Lombardo, and Zannier, we prove a slightly weaker statement. Namely, assuming A(k) is dense, we show that the complement of the image of X(k) in A(k) is (still) dense, i.e., there are less points on X than there are on A (or: there are more points on A than on X). In this talk I will explain how our proof relies on interpreting this as a special case of a version of Hilbert’s irreducibility theorem for abelian varieties.

BGU Probability and Ergodic Theory (PET) seminar

Allosteric actions of surface groups Online

Nov 11, 11:10—12:00, 2021, -101


Matthieu Joseph (École normale supérieure de Lyon)


In a recent work, I introduced the notion of allosteric actions: a minimal action of a countable group on a compact space, with an ergodic invariant measure, is allosteric if it is topologically free but not essentially free. In the first part of my talk I will explain some properties of allosteric actions, and their links with Invariant Random Subgroups (IRS) and Uniformly Recurrent Subgroups (URS). In the second part, I will explain a recent result of mine: the fundamental group of a closed hyperbolic surface admits allosteric actions.

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