2020 Nov 16

AG & NT lunch seminar: José Ibrahim Villanueva Gutiérrez, "Iwasawa main conjecture"

1:00pm to 2:00pm

Speaker:   José Ibrahim Villanueva Gutiérrez

Title:  "Iwasawa main conjecture"

Abstract: Iwasawa main conjecture, which is actually a theorem (Mazur & Wiles
84), fulfills the relations between arithmetic objects, p-adic L-functions and complex 
L-functions. In this talk we sketch how these relations arise and give some consequences.
2020 Nov 11

Logic Seminar - Ori Segal

11:15am to 1:00pm


Meeting ID: 868 3879 6860 Passcode: 175603

Boolean Types in Dependent Theories
(Joint work with Itay Kaplan and Saharon Shelah)

Abstract: Complete types, seen as ultrafilters, are naturally equivalent to Boolean homomorphisms to {0,1}.
The notion of a complete type can thus be generalized in a natural manner to allow assigning a value in an arbitrary Boolean algebra to each formula, and this notion is particularily well behaved when the ambient theory has NIP.
I will show that this notion generalizes, in a sense, both complete types and Keisler measures.
2020 Nov 17

Dynamics seminar (special hour): Yinon Spinka (UBC) Phase transitions and finitary codings

6:00pm to 7:00pm

Abstract: In this talk we will explore the connection between the two seemingly unrelated concepts appearing in the title. Phase transitions occur when a system undergoes an abrupt change in behaviour as a consequence of a small change in parameters. While phase transitions are evidently observed in the physical world (e.g., water freezing or evaporating), they are also ubiquitous in mathematical problems studied in statistical mechanics, probability, combinatorics and computer science.
2020 Dec 24

Colloquium: Nathan Keller (BIU) — Can you hear the shape of a low-degree Boolean function?

2:30pm to 3:30pm

Analysis of Boolean functions aims at "hearing the shape" of functions on the discrete cube {-1,1}^n — namely, at understanding what the structure of the (discrete) Fourier transform tells us about the function. 
In this talk, we focus on the structure of "low-degree" functions on the discrete cube, namely, on functions whose Fourier coefficients are concentrated on "low" frequencies. While such functions look very simple, we are surprisingly far from understanding them well, even in the most basic first-degree case. 
2020 Nov 26

Colloquium: Barak Sober (Duke) — Estimation of Manifolds from Point Clouds: Building Models from Data

2:30pm to 3:30pm

A common observation in data-driven applications is that data has a low intrinsic dimension, at least locally.
Thus, when one wishes to work with data that is not governed by a clear set of equations, but still wishes to perform statistical or other scientific analysis, an optional model is the assumption of an underlying manifold from which the data was sampled.
This manifold, however, is not given explicitly but we can obtain samples of it (i.e., the individual data points).
2020 Nov 03

Dynamics lunch seminar: Elon Lindenstrauss (HUJI) - Bernoulli decomposition and arithmetical independence between sequence, following Yu and Austin

12:00pm to 1:00pm

The relevant papers I will be describing are:

Han Yu. Bernoulli decomposition and arithmetical independence between sequences. Erg. Th. and Dy-
nam. Sys., 1–11, 2020.

Tim Austin. A new dynamical proof of the Shmerkin--Wu theorem

Zoom meeting details (lunch seminar):

Join Zoom Meeting
Meeting ID: 860 3036 4068
2020 Dec 09

Analysis seminar (SPECIAL TIME!): Nadav Dym (Duke) — Phase retrieval stability via notions of graph connectivity

4:00pm to 5:00pm

Phase retrieval is the inverse problem of reconstructing a signal from linear measurements, when the phase of the measurements is lost and only the magnitude is known. This problem occurs in many applications including crystallography, optics, and acoustics.

2020 Nov 04

Graduate Student Seminar - Geva Yashfe and Moshe White

4:00pm to 6:00pm


Join Zoom Meeting Meeting ID: 836 9890 9188 Passcode: 392656

First Talk: 16:00-17:00

Geva Yashfe: The principal kinematic formula: Euler characteristic and geometry

Abstract: Let C and D be nice domains in R^d. Given some geometric data on each of the domains, the principal kinematic formula computes an integral over the group of rigid motions of R^d: it sums the Euler characteristic of the intersection of C with g.D as g ranges over the group.