Game Theory | Yevgeny Tsodikovich

About Me

I'm a Postdoctoral Researcher at the Department of Economics at Bar-Ilan University, Israel. Prior to joining Bar-Ilan, I was a PostDoc at the Aix-Marseille School of Economics.

I completed my Ph.D. in mathematics, specializing in Game Theory, at Tel Aviv University under the supervision of Prof. Ehud Lehrer.

My main research interest is opinion dynamics and learning in networks, but I enjoy exploring other realms of game theory and economics. My Job Market Paper deals with the minimal contagious set for growing networks with a converging degree distribution, such as the common scale-free network.

Selected publications

Research

Teaching

I taught undergraduate probability and statistics courses for engineers at Tel Aviv University as a lecturer and a T.A. In addition, I worked at the Open University where I taught Game Theory and Linear Algebra in the Mathematics Department.

Selected Publications

Minimal contagious sets in innovation diffusion networks

with Itai Arieli, Galit Ashkenazi-Golan & Ron Peretz; R&R at JET; Job market paper

We investigate the minimal seed size required for successful innovation adoption in networks of growing size, such as scale-free networks, which are widely used to model real-world social networks. We use the bootstrap percolation dynamics model, where agents adopt the innovation if a certain fraction of their neighbors has already adopted it. Our main contribution is to provide an upper and lower bound on the size of the seed set and to prove that in growing networks, the minimal seed required to reach the entire network cannot be sub-linear in the network size. We demonstrate this result through simulations. Our study contributes to a better understanding of innovation diffusion in scale-free networks and offers potential applications in marketing, public health, and social policy. Our results provide a theoretical foundation for future research to investigate optimal seeding strategies in more complex network structures and dynamics.

I want to tell you? Maximizing revenue in first-price two-stage auctions

with Galit Ashkenazi-Golan & Yannick Viossat. Economic Theory (2023)

A common practice in many auctions is to offer bidders an opportunity to improve their bids, known as a best and final offer stage. This improved bid can depend on new information either about the asset or about the competitors. This paper examines the effects of new information regarding competitors, seeking to determine what information the auctioneer should provide assuming the set of allowable bids is discrete. The rational strategy profile that maximizes the revenue of the auctioneer is the one where each bidder makes the highest possible bid that is lower than his valuation of the item. This strategy profile is an equilibrium for a large enough number of bidders,
regardless of the information released. We compare the number of bidders needed for this profile to be an equilibrium under different information structures.We find that it becomes an equilibrium with fewer bidders when less additional information is made available to the bidders regarding the competition. It follows that when the number of bidders is a priori unknown, there are some advantages to the auctioneer not revealing
information and conducting a one-stage auction instead.

The Regularity of the Value Function of Repeated Games with Switching Costs

with Xavier Venel & Anna Zseleva. Mathematics of Operations Research (2023)

We study repeated zero-sum games where one of the players pays a certain cost each time he changes his action. We derive the properties of the value and optimal strategies as a function of the ratio between the switching costs and the stage payoffs. In particular,
the strategies exhibit a robustness property and typically do not change with a small perturbation of this ratio. Our analysis extends partially to the case where the players are limited to simpler strategies that are history independent-namely, static strategies. In this case, we also characterize the (minimax) value and the strategies for obtaining it.