Publications

Poisson search (with F. De Sinopoli and L. Ferraris), Journal of Mathematical Economics, 112, 102981.

We present a model of the job market where the number of workers and companies is uncertain, representing the job search activity as a Poisson game. We allow for heterogeneity of workers and companies and show that in equilibrium more productive types choose higher terms of trade. The Poisson search model gives rise to multiple, possibly inefficient equilibria.

Poisson-Cournot games (with F. De Sinopoli, C. Kunstler, and C. Pimienta), Economic Theory, 2023.

We construct a Cournot model in which firms have uncertainty about the total number of firms in the industry. We model such an uncertainty as a Poisson game and we characterize the set of equilibria after deriving some novel properties of the Poisson distribution. When the marginal cost is zero, the number of equilibria increases with the expected number of firms (n) and for n ≥ 3 every equilibrium exhibits overproduction relative to the model with deterministic population size. Overproduction is robust to sufficiently small marginal costs, however, for a fixed marginal cost, the set of equilibria approaches the equilibrium quantity of the deterministic model as n goes to infinity.

Poisson voting games under proportional rule (with F. De Sinopoli), Social Choice and Welfare, 2022.

We analyze strategic voting under proportional rule and two parties, embedding the basic spatial model into the Poisson framework of population uncertainty. We prove that there exists a unique Nash equilibrium. We show that it is characterized by a cutpoint in the policy space that is always located between the average of the two parties' positions and the median of the distribution of voters' types. We also show that, as the expected number of voters goes to infinity, the equilibrium converges to that of the case with deterministic population size.

Towards a solution concept for network formation games (with A. Gallo), Economics Letters, 2021.

Network formation games (Myerson, 1991) typically present a multiplicity of Nash equilibria. Some of them are such that mutually beneficial links are not formed, thus inducing networks that are not pairwise stable. We offer an equilibrium refinement for this class of games which naturally involves pairwise stability while guaranteeing admissibility.

Tournament-stable equilibria (with F. De Sinopoli and C. Pimienta), Journal of Mathematical Economics, 2020.

Building on Arad and Rubinstein (2013), we introduce tournaments as simultaneous n-player games based on an m-player game g. A player meets each group of m−1 opponents m! times to play g in alternating roles. The winner of the tournament is the player who attains the highest accumulated score. We explore the relationship between the equilibria of the tournament and the equilibria of the game g and confirm that tournaments provide a refinement criterion. We compare it with standard refinements in the literature and show that it is satisfied by strict equilibria. We use our tournament model to study a selection of relevant economic applications, including risk-taking behavior.

A concept of sincerity for combinatorial voting (with F. De Sinopoli), Social Choice and Welfare, 2018.

A basic problem in voting theory is that all the strategy profiles in which nobody is pivotal are Nash equilibria. We study elections where voters decide simultaneously on several binary issues. We extend the concept of conditional sincerity introduced by Alesina and Rosenthal (Econometrica 64(6):1311–1341, 1996) and propose an intuitive and simple criterion to refine equilibria in which players are not pivotal. This is shown to have a foundation in a refinement of perfection that takes into account the material voting procedure. We prove that in large elections the proposed solution is characterized through a weaker definition of Condorcet winner and always survives sophisticated voting.

Electoral competition with strategic voters, Economics Letters, 2017.

A recent literature has found a positive relationship between the disproportionality of the electoral system and the convergence of parties’ positions. Such a relationship depends crucially on the assumption that voting is sincere. We show that, when voters are players in the game and not simply automata that vote for their favorite party, two policy-motivated parties always take extreme positions in equilibrium.

The structure of Nash equilibria in Poisson games (with C. Pimienta), Journal of Economic Theory, 2017.

We show that many results on the structure and stability of equilibria in finite games extend to Poisson games. In particular, the set of Nash equilibria of a Poisson game consists of finitely many connected components and at least one of them contains a stable set (De Sinopoli et al., 2014). In a similar vein, we prove that the number of Nash equilibria in Poisson voting games under plurality, negative plurality, and (when there are at most three candidates) approval rule, as well as in Poisson coordination games, is generically finite. As in finite games, these results are obtained exploiting the geometric structure of the set of Nash equilibria which, in the case of Poisson games, is shown to be semianalytic.

Strategic stability in Poisson games (with F. De Sinopoli and C. Pimienta), Journal of Economic Theory, 2014. 

In Poisson games, an extension of perfect equilibrium based on perturbations of the strategy space does not guarantee that players use admissible actions. This observation suggests that such a class of perturbations is not the correct one. We characterize the right space of perturbations to define perfect equilibrium in Poisson games. Furthermore, we use such a space to define the corresponding strategically stable sets of equilibria. We show that they satisfy existence, admissibility, and robustness against iterated deletion of dominated strategies and inferior replies.

Working Papers

Group size as selection device (with F. De Sinopoli and L. Ferraris).

In a coordination game with multiple Pareto ordered equilibria and population uncertainty, we show that group size helps select a unique equilibrium, for reasons reminiscent of the global games literature. A critical mass phenomenon emerges at equilibrium. Group size has an emboldening effect on participants.