Seminars

2017 May 14

Game Theory & Math Economics: Oscar Volij (BGU) - "Segregation by Income." (Joint with Casilda Lasso de la Vega)

4:00pm to 5:00pm

Location: 

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
We provide an axiomatic characterization of an income segregation index in school districts. One axiom requires that single-school districts be the least segregated of all districts. A second axiom requires that any reorganization of a subdistrict that raises its segregation, raises the districtwide segregation as well. A third axiom requires an intuitive decomposition by subdistricts into within-district and between-district terms.
2017 May 21

Game Theory & Math Economics: Ori Heffetz (HUJI) - "What do lab experiments say about the Koszegi-Rabin theory of reference-dependent preferences?"

4:00pm to 5:00pm

Location: 

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
Koszegi and Rabin’s (2006, 2007, 2009) model of expectations-based reference-dependent preferences offers a unified explanation for a diverse body of evidence across different domains. However, almost a decade of direct lab tests of the model has generated mixed evidence: in only a subset of (what appear to be) similar experimental setups are lagged-probability-beliefs treatments found to affect behavior as (apparently) predicted by the theory. The present paper aims to investigate why.
2017 Jun 25

Game Theory & Math Economics: Yaniv Dover (HUJI) - "Promotional Reviews: An Empirical Investigation of Online Review Manipulation"

4:00pm to 5:00pm

Location: 

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
Online reviews could, in principle, greatly improve the match between consumers and products. However, the authenticity of online user reviews remains a concern; firms have an incentive to manufacture positive reviews for their own products and negative reviews for their rivals. In this paper, we marry the diverse literature on economic subterfuge with the literature on organizational form. We undertake an empirical analysis of promotional reviews, examining both the extent to which fakery occurs and the market conditions that encourage or discourage promotional reviewing activity.
2017 Oct 29

Game Theory & Math Economics: Rann Smorodinsky (Technion) - "Bayesian learning in markets with common value"

4:00pm to 5:00pm

Location: 

Elath Hall, 2nd floor, Feldman Building, Edmond J. Safra Campus
Two  firms produce substitute goods with unknown quality. At each stage the firms set prices and a consumer with private information and unit demand buys from one of the fi rms. Both  firms and consumers see the entire history of prices and purchases. Will such markets aggregate information? Will the superior  rm necessarily prevail? We adapt the classical social learning model by introducing strategic dynamic pricing. We provide necessary and sufficient conditions for learning. In contrast to previous results, learning can occur when signals are bounded.
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 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
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.

Pages