Seminars

2017 Nov 12

Game Theory & Math Economics: Chang Zhao (Tel-Aviv University) - "Optimal Dynamic Inspection" (joint work with Eilon Solan)

4:00pm to 5:00pm

Location: 

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

We study a discounted repeated inspection game with two agents and one principal. Both agents may profit by violating certain rules, while the principal can inspect on at most one agent in each period, inflicting a punishment on an agent who is caught violating the rules. The goal of the principal is to minimize the discounted number of violations, and he has a Stackelberg leader advantage. We characterize the principal's optimal inspection strategy.

2017 Nov 19

Game Theory & Math Economics: Eilon Solan (Tel-Aviv University) - "Quitting Games and Linear Complementarity Problems" (joint work with Omri N. Solan)

4:00pm to 5:00pm

Location: 

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
We prove that every multiplayer quitting game admits a sunspot epsilon-equilibrium for every epsilon > 0, that is, an epsilon-equilibrium in an extended game in which the players observe a public signal at every stage. We also prove that if a certain matrix that is derived from the payoff s in the game is a Q-matrix in the sense of linear complementarity problems, then the game admits a Nash epsilon-equilibrium for every epsilon > 0.
2017 Nov 26

Game Theory & Math Economics: Rasmus Ibsen-Jensen (IST Austria) - "Computational Complexity of Evolutionary Games on Graphs"

4:00pm to 5:00pm

Location: 

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
The talk will consider evolutionary games on graphs, which is a generalization of matrix games to graphs, using the solution concept of evolutionary stable strategies. In evolutionary games on graphs, there is a graph and a 2x2 matrix. Each node of the graph has a strategy of the matrix game - r or b - and initially all nodes are r. Then, a uniformly random node is made to follow b and the following is repeated until the graph is all one strategy again:1. Find the average payoff of each node when playing against their neighbors in the graph (depending on their current strategies).2.
2017 Dec 10

Game Theory & Math Economics: Simina Brânzei (HUJI) - "Universal Growth in Exchange Economies"

11:30am to 1:00pm

Location: 

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
We show that a simple decentralized dynamic, where players update theirbids proportionally to how useful the investments were, leads to growth ofthe economy in the long term (whenever growth is possible) but also createsunbounded inequality, i.e. very rich and very poor players emerge. Weanalyze several other phenomena, such as how the relation of a player withothers influences its development and the Gini index of the system.Joint work with Ruta Mehta and Noam Nisan.
2018 May 02

Analysis Seminar: Bo'az Klartag "Convex geometry and waist inequalities"

12:00pm to 1:00pm

Location: 

room 70, Ross Building
Abstract: We will discuss connections between Gromov's work on isoperimetry of waists and Milman's work on the M-ellipsoid of a convex body. It is proven that any convex body K in an n-dimensional Euclidean space has a linear image K_1 of volume one satisfying the following waist inequality: Any continuous map f from K_1 to R^d has a fiber f^{-1}(t) whose (n-d)-dimensional volume is at least c^{n-d}, where c > 0 is a universal constant. Already in the case where f is linear, this constitutes a slight improvement over known results.
2018 Jun 06

Analysis Seminar: Michal Pnueli "Dynamics in a Hamiltonian Impact System"

12:00pm to 1:00pm

Location: 

Ross Building, Room 70
Abstract: Hamiltonian impact systems are dynamical systems in which there are two main mechanisms which dictate the system’s behavior - Hamilton’s equations which govern the motion inside the impact system domain, and the billiard reflection rule which governs the motion upon reaching the domain boundary. As the dynamics in impact systems are piecewise smooth by nature due to the collisions with the boundary, many of the traditional tools used in the analysis of Hamiltonian systems cannot be applied to impact systems in a straightforward manner. This talk will present a
2016 Jun 09

Joint Amitsur Algebra&NT Seminar: Shai Haran (Technion), "New foundations for geometry"

12:00pm to 1:15pm

Location: 

Manchester Building (Ross 63), Jerusalem, Israel
*** Please note the LOCATION *** We shall give a simple generalization of commutative rings. The category GR of such generalized rings contains ordinary commutative rings (fully, faithfully), but also the "integers" and the "residue field" at a real or complex place of a number field ; the "field with one element" F1 (the initial object of GR) ; the "Arithmetical Surface" (the categorical sum of the integers Z with them self). We shall show this geometry sees the real and complex places of a number field K : the valuation sub GR of K correspond to the finite and
2016 Apr 21

Amitsur Algebra: Konstantin Golubev (HU)

12:00pm to 1:15pm

Location: 

Manchester Building (room 209), Jerusalem, Israel
Title: Spectral approach to the chromatic number of a simplicial complex Abstract: In this talk, we'll summarize results obtained in recent years in a pursuit for spectral bounds for the chromatic number of a simplicial complex. As the principal application, we'll show that Ramanujan complexes serve as family of explicitly constructed complexes with large girth and large chromatic number. We'll also present other results, such as a bound on the expansion and a bound on the mixing of a complex, and refer to open questions. Based on joint work with S.Evra, A.Lubotzky and O.Parzanchevski.

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