• 2018 Oct 18

# Zabrodsky Lectures: Prof. Rahul Pandharipande (ETH Zurich)

Thu, 18/10/2018 (All day) to Mon, 22/10/2018 (All day)

• 2018 Oct 21

# Feldenkrais and Mathematics

Sun, 21/10/2018 (All day) to Tue, 23/10/2018 (All day)

## Location:

Israel Institute for Advanced Studies, The Hebrew University of Jerusalem
• 2018 Oct 21

# Zabrodsky Lecture 2: Cohomological Field Theories

## Lecturer:

Rahul Pandharipande (ETH Zurich)
11:00am to 12:00pm

## Location:

Ross 70
Cohomological Field Theories (CohFTs) were introduced to keep track of the classes on the moduli spaces of curves defined by Gromov-Witten theories and their cousins. I will define CohFTs (following Kontsevich-Manin), explain the classification in the semisimple case of Givental-Teleman, and discuss the application to Pixton's relations which appear in the first lecture.
• 2018 Oct 21

# Kazhdan seminar: Tomer Schlank "The Nonabelian Chabauty Method"

Repeats every week every Sunday, 14 times .
12:00pm to 2:00pm

## Location:

Ross 70A
Abstract: The Chabauty method is a remarkable tool which employs p-adic analitic methods (in particular Colman integration.) To study rational points on curves. However the method can be applied only when the genus of the curve in question is larger than its Mordell-Weil rank. Kim developed a sophisticated "nonableian" generalisation. We shall present the classical methid, and give an approachable introduction to Kim's method. I'm basically going to follow http://math.mit.edu/nt/old/stage_s18.html
• 2018 Oct 21

# Kazhdan seminar: Karim Adiprasito "Positivity in combinatorics and beyond"

Repeats every week every Sunday, 14 times .
3:00pm to 5:00pm

## Location:

Ross 70A
Abstract: I will discuss applications of algebraic results to combinatorics, focusing in particular on Lefschetz theorem, Decomposition theorem and Hodge Riemann relations. Secondly, I will discuss proving these results combinatorially, using a technique by McMullen and extended by de Cataldo and Migliorini. Finally, I will discuss Lefschetz type theorems beyond positivity. Recommended prerequisites: basic commutative algebra
• 2018 Oct 22

# Combinatorics: Spencer Backman, HU, "Cone valuations, Gram's relation, and flag-angles"

11:00am to 1:00pm

## Location:

Rothberg CS building, room B500, Safra campus, Givat Ram
Speaker: Spencer Backman, HU Title: Cone valuations, Gram's relation, and flag-angles
• 2018 Oct 22

# NT & AG Lunch: Jasmin Matz "Modular forms"

1:00pm to 2:00pm

## Location:

Faculty lounge, Math building
Abstract: Modular forms are historically the first example of automorphic forms, and are still studied today as they have many applications. In this talk I want to introduce modular forms, give some examples, and, if time permits, explain the connection to elliptic curves, objects we already met in the first lecture.
• 2018 Oct 22

# Zabrodsky Lecture 3: CohFT calculations

## Lecturer:

Rahul Pandharipande (ETH Zurich)
2:00pm to 3:00pm

## Location:

Ross 70
I will explain how calculations of various natural classes on the moduli of curves fit into the CohFT framework. These include calculations related to Hilbert schemes of points, Verlinde bundles, and, if time permits, double ramification (DR) cycles.
• 2018 Oct 23

# Dynamics Lunch: Amir Algom "On \alpha \beta sets."

12:00pm to 1:00pm

## Location:

Manchester faculty club
Let $\alpha, \beta$ be elements of infinite order in the circle group. A closed set K in the circle is called an \alpha \beta set if for every x\in K either x+\alpha \in K or x+\beta \in K. In 1979 Katznelson proved that there exist non-dense \alpha \beta sets, and that there exist \alpha \beta sets of arbitrarily small Hausdorff dimension. We shall discuss this result, and a more recent result of Feng and Xiong, showing that the lower box dimension of every \alpha \beta set is at least 1/2.
• 2018 Oct 23

# Dynamics Seminar: Nishant Chandgotia (HUJI). Some universal models for Z^d actions

2:15pm to 3:15pm

## Location:

Ross 70
Krieger’s generator theorem shows that any free invertible ergodic measure preserving action (Y,\mu, S) can be modelled by A^Z (equipped with the shift action) provided the natural entropy constraint is satisfied; we call such systems (here it is A^Z) universal. Along with Tom Meyerovitch, we establish general specification like conditions under which Z^d-dynamical systems are universal. These conditions are general enough to prove that 1) A self-homeomorphism with almost weak specification on a compact metric space (answering a question by Quas and Soo)