2017 Jun 15

# Analysis and PDEs, "Quantum state transfer on graphs", G. Lippner (neu)

1:00pm to 2:00pm

## Location:

Ross 70
Title: Quantum state transfer on graphs. Abstract: Transmitting quantum information losslessly through a network of particles is an important problem in quantum computing. Mathematically this amounts to studying solutions of the discrete Schrödinger equation d/dt phi = i H phi, where H is typically the adjacency or Laplace matrix of the graph. This in turn leads to questions about subtle number-theoretic behavior of the eigenvalues of H.
2016 Jul 30

# לכתוב מייל למורי תכנית הנשיא על פגישה ב-14.8

10:00am to 11:00am

2017 Nov 15

# Jerusalem Analysis Seminar: "Operators and random walks", Gady Kozma (Weizmann Institute)

12:00pm to 1:00pm

## Location:

Ross 70 (NOTE LOCATION!)
Abstract: We will discuss the question: for a random walk in a random environment, when should one expect a central limit theorem, i.e. that after appropriate scaling, the random walk converges to Brownian motion? The answer will turn out to involve the spectral theory of unbounded operators. All notions will be defined in the talk. Joint work with Balint Toth.
2017 Mar 09

# Analysis and PDEs: Iosif Polterovich (Montreal) - Nodal Geometry of Steklov Eigenfunctions

12:00pm to 1:00pm

## Location:

Ross 70
I will present an overview of some recent progress on the study of the nodal sets of Steklov eigenfunctions. In particular, I will discuss sharp estimates on the nodal length of Steklov eigenfunctions on real-analytic Riemannian surfaces with boundary obtained in my joint work with D. Sher and J. Toth.
2017 Nov 16

2:00pm to 3:00pm

2017 Jun 29

# Special Seminar: Ayala Byron (HUJI) "Homogeneity of torsion-free hyperbolic groups"

2:00pm to 3:00pm

## Location:

Ross 70
Abstract: A (countable) group G is homogeneous if whenever g,h are tupples of the same type in G, there is an automorphism of G sending g to h. We give a characterization of freely-indecomposable torsion-free hyperbolic groups which are homogeneous, in terms of a particular decomposition as a graph of groups - their JSJ decomposition. This is joint work with Chloe Perin. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts.
2017 May 09

# Topology & Geometry Seminar: Serap Gurer (Galatasaray University), "(Co)homology theories on diffeological spaces".

11:00am to 12:00pm

## Location:

Ross A70.
Abstract: In this talk, I will introduce diffeological spaces and some (co)homology theories on these spaces. I will also talk on Thom-Mather spaces and their (co)homology in the diffeological context.
2017 Aug 09

# Topology and Geometry Seminar: "Bordered methods in knot Floer homology" Peter Ozsvath, Princeton University

12:00pm to 1:00pm

## Location:

Ross 70A
Abstract: Knot Floer homology is an invariant for knots in the three-sphere defined using methods from symplectic geometry. I will describe a new algebraic formulation of this invariant which leads to a reasonably efficient computation of these invariants. This is joint work with Zoltan Szabo.
2017 Jun 13

# Topology and Geometry Seminar: Alexander Caviedes Castro (Tel-Aviv University), "Symplectic capacities and Cayley graphs"

1:00pm to 1:50pm

## Location:

Ross 70A
Abstract: The Gromov non-squeezing theorem in symplectic geometry states that is not possible to embed symplectically a ball into a cylinder of smaller radius, although this can be done with a volume preserving embedding. Hence, the biggest radius of a ball that can be symplectically embedded into a symplectic manifold can be used as a way to measure the "symplectic size'' of the manifold. We call the square of this radius times the number \pi the Gromov width of the symplectic manifold. The Gromov width as a symplectic invariant is extended through the notion of "Symplectic Capacity".
2017 May 10

# Peli Grietzer (Harvard literature dept.)

4:00pm to 5:00pm

## Location:

Ross 70.
Abstract: In 1962, amateur literary theorist and professional mathematician Andrey Kolmogorov wrote: ‘A story is art only if the characters and situations it describes stand a chance of becoming
2017 Oct 23

# HD-Combinatorics: Nati Linial, "High-dimensional permutations"

2:00pm to 4:00pm

## Location:

Israel Institute for Advanced Studies (Feldman building, Givat Ram), Eilat Hall
This is a survey talk about one of the main parts of what we call high-dimensional combinatorics. We start by equating a permutation with a permutation matrix. Namely, an nxn array of zeros and ones where every line (=row or column) contains exactly one 1. In general, a d-dimensional permutation is an array [n]x[n]x....x[n] (d+1 factors) of zeros and ones in which every line (now there are d+1 types of lines) contains exactly one 1. Many questions suggest themselves, some of which we have already solved, but many others are still wide opne. Here are a few examples:
2018 Jan 15

# HD-Combinatorics: Alexander Gamburd, "Arithmetic and Dynamics on Markoff-Hurwitz Varieties"

2:00pm to 4:00pm

## Location:

IIAS, Feldman Building, Givat Ram
Markoff triples are integer solutions to Markoff equation $x^2+y^2+z^2=3xyz$ which arose in Markoff's spectacular and fundamental work (1879) on diophantine approximation and has been henceforth ubiquitous in a tremendous variety of different fields in mathematics and beyond.
2017 Nov 06

4:00pm to 6:00pm

Room 130
2017 Nov 13

# HD-Combinatorics: Shmuel Weinberger, "L^2 cohomology"

2:00pm to 4:00pm

## Location:

Room 130, Feldman Building, Givat Ram
Abstract: I will give an introduction to the cohomology of universal covers of finite complexes. These groups are (for infinite covers) either trivial or infinite dimensional, but they have renormalized real valued Betti numbers. Their study is philosophically related to the topic of our year, and they have wonderful applications in geometry, group theory, topology etc and I hope to explain some of this.