2018
Jan
29

# Seminars

2018
Jan
24

2018
Jan
17

2017
Dec
05

# T&G: Michael Farber (IIAS), Robot motion planning and Bredon equivariant cohomology

12:00pm to 1:30pm

## Location:

Room 70A, Ross Building, Jerusalem, Israel

I will describe a topological approach to the robot motion planning problem focusing mainly on the case of aspherical configuration spaces.

2018
Jan
29

# HD-Combinatorics Special day: Pseudo-randomness (organised by Uli Wagner)

10:00am to 5:00pm

## Location:

IIAS, Feldman Building, Givat Ram

10:00-11:00

11:30-12:30

13:45- 14:45

15:00-16:00

16:30-17:30

**Anna Gundert**/**Uli Wagner**- Quasirandomness and expansion for graphs11:30-12:30

**Anna Gundert**/**Uli Wagner**- Quasirandomness for hypergraphs13:45- 14:45

**Uli Wagner**- Szemeredi's regularity lemma for dense graphs15:00-16:00

**Tamar Ziegler**- Gowers uniformity norms16:30-17:30

**Anna Gundert**/**Uli Wagner**- Hypergraph regularity
2018
Feb
12

2017
Dec
24

# Game Theory & Math Economics: Yonatan Aumann (Bar - Ilan) - "On Time Discounting, Impatience and Risk Aversion"

4:00pm to 4:30pm

## Location:

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus

Time discounting is a ubiquitous assumption in economic literature. We (re)explore the foundations of such time preferences. "Impatience" is defined as a preferences for experiencing the better states sooner rather than later, even when there is no uncertainty associated with the future. We show that, assuming consistency and some weak stationarity assumptions, impatience is incompatible with a meaningful notion of a risk-attitude (risk aversion/love/neutrality).On the other hand, if there is uncertainty associated with the future then discounting necessarily emerges.

2017
Dec
10

# Game Theory & Math Economics: Sergiu Hart (HUJI)

4:00pm to 4:30pm

## Location:

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus

A unified integral approach to all the calibration results in the literature -- from regular probabilistic calibration to smooth deterministic calibration -- using simple "hairy" fixed point and minimax results.

2018
Jan
14

# Game Theory & Math Economics: Harry Dankowicz (UIUC) "Emergent Task Differentiation on Network Filters"

4:00pm to 4:30pm

## Location:

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus

Inspired by empirical observations on honey bee colonies, we analyze the emergence of task differentiation in a model complex system, characterized by an absence of hierarchical control, yet able to exhibit coordinated behavior and collective function. The analysis considers the steady-state response of a mechanical interaction network to exogenous resonant excitation.

2018
Jan
21

2018
Jan
21

2015
Nov
25

# Topology & geometry: Lara Simone Suárez (HUJI), "Exact Lagrangian cobordism and pseudo-isotopy"

11:00am to 12:45pm

## Location:

Ross building, Hebrew University (Seminar Room 70A)

Abstract: Consider two Lagrangian submanifolds L, L′ in a symplectic manifold (M,ω). A Lagrangian cobordism (W;L,L′) is a smooth cobordism between L and L′ admitting a Lagrangian embedding in (([0,1]×R)×M,(dx∧dy)⊕ω) that looks like [0,ϵ)×{1}×L and (1−ϵ,1]×{1}×L′ near the boundary.
In this talk we will show that under some topological constrains, an exact Lagrangian cobordism (W;L,L′) with dim(W)>5 is diffeomorphic to [0,1]×L.

2017
Jun
01

# Group actions:Lei Yang - badly approximable points on curves and unipotent orbits in homogeneous spaces

10:30am to 11:30am

We will study n-dimensional badly approximable points on curves. Given an analytic non-degenerate curve in R^n, we will show that any countable intersection of the sets of weighted badly approximable points on the curve has full Hausdorff dimension. This strengthens a previous result of Beresnevich by removing the condition on weights. Compared with the work of Beresnevich, we study the problem through homogeneous dynamics. It turns out that the problem is closely related to the study of distribution of long pieces of unipotent orbits in homogeneous spaces.

2018
Jan
22

2017
Apr
20

# Basic notions: Raz Kupferman (HUJI) - A geometric framework for continuum mechanics

4:00pm to 5:15pm

Abstract:
The “geometrization" of mechanics (whether classical, relativistic or quantum) is almost as old as modern differential geometry, and it nowadays textbook material.
The formulation of a mathematically-sound theory for the mechanics of continuum media is still a subject of ongoing research. In this lecture I will present a geometric formulation of continuum mechanics, starting with the definition of the fundamental physical observables, e.g., force, deformation, stress and traction. The outcome of this formulation is a generalization of Newton’s "F=ma” equation for continuous media.