arXiv subjects

David Lagziel

Publications and source records attributed to David Lagziel.

8 recordsLinked to original sources

arXiv2026

Public Information Generators: Common Knowledge and Information Loops

We analyze incomplete-information games where an oracle publicly shares information with privately informed players. One oracle dominates another if, for every experiment of the latter, it can choose an experiment that supports, in every game, every equilibrium outcome distribution induced by the other. We fully characterize equivalence (mutual dominance) and identify the information-loop obstruction governing one-sided dominance, obtaining necessity in general and sufficiency under separated-loop structures. The analysis highlights the role of common-knowledge components and develops a theory of information loops, thereby extending the seminal work of Blackwell (1951) to strategic environments and Aumann (1976)'s theory of common knowledge.

econ.TH↗

arXiv2026

Comparison of Deterministic Information Providers

We analyze incomplete-information games where an oracle publicly shares information with players. One oracle dominates another if, in every game, it can match the set of equilibrium outcomes induced by the latter. Characterizations are provided for deterministic signaling functions, based on simultaneous posterior matching, a constructive partition criterion, and common knowledge components. This study elaborates on the work of Blackwell (1951) in games with incomplete information, using the common knowledge components of Aumann (1976).

econ.TH↗

arXiv2025

Mechanism Design with Spiteful Agents

We study a mechanism-design problem in which spiteful agents strive to not only maximize their rewards but also, contingent upon their own payoff levels, seek to lower the opponents' rewards. We characterize all individually rational (IR) and incentive-compatible (IC) mechanisms that are immune to such spiteful behavior, showing that they take the form of threshold mechanisms with an ordering of the agents. Building on this characterization, we prove two impossibility results: under either anonymity or efficiency, any such IR and IC mechanism collapses to the null mechanism, which never allocates the item to any agent. Leveraging these findings, we partially extend our analysis to a multi-item setup. These results illuminate the challenges of auctioning items in the natural presence of other-regarding preferences.

cs.GT↗

arXiv2025

Constrained Mediation: Bayesian Implementability of Joint Posteriors

We examine information structures in settings with privately informed agents and an informationally constrained mediator who supplies additional public signals. Our focus is on characterizing the set of posteriors that the mediator can induce. To this end, we employ a graph-theoretic framework: states are represented as vertices, information sets correspond to edges, and a likelihood ratio function on edges encodes the posterior beliefs. Within this framework, we derive necessary and sufficient conditions, internal and external consistency, for the rationalization of posteriors. Finally, we identify conditions under which a single mediator can implement multiple posteriors, effectively serving as a generator of Blackwell experiments.

econ.TH↗

arXiv2025

Comparison of Oracles: Part II

This paper studies incomplete-information games in which an information provider, an oracle, publicly discloses information to the players. One oracle is said to dominate another if, in every game, it can replicate the equilibrium outcomes induced by the latter. The companion Part I characterizes dominance under deterministic signaling and under stochastic signaling with a unique common knowledge component. The present paper extends the analysis to general environments and provides a characterization of equivalence (mutual dominance) among oracles. To this end, we develop a theory of information loops, thereby extending the seminal work of Blackwell (1951) to strategic environments and Aumann (1976)'s theory of common knowledge.

econ.TH↗

arXiv2023

The Indoctrination Game

The indoctrination game is a complete-information contest over public opinion. The players exert costly effort to manifest their private opinions in public in order to control the discussion, so that the governing opinion is similar to theirs. Our analysis provides a theoretical foundation for the silent majority and vocal minority phenomena, i.e., we show that all moderate opinions remain mute in equilibrium while allowing extremists full control of the discussion. Moreover, we prove that elevated exposure to others' opinions increases the observed polarization among individuals. Using these results, we formulate a new social-learning framework, referred to as an indoctrination process.

econ.TH↗

arXiv2022

Dynamic screening

We study dynamic screening problems where elements are subjected to noisy evaluations and, in every stage, some of the elements are rejected while the remaining ones are independently re-evaluated in subsequent stages. We prove that, ceteris paribus, the quality of a dynamic screening process is not monotonic in the number of stages. Specifically, we examine the accepted elements' values and show that adding a single stage to a screening process may produce inferior results, in terms of stochastic dominance, whereas increasing the number of stages substantially leads to a first-best outcome.

econ.TH↗

arXiv2015

On the Failures of Bonus Plans

A decision maker (DM) has some funds invested through two investment firms. She wishes to allocate additional funds according to the firms' earnings. The DM, on the one hand, tries to maximize the total expected earnings, while the firms, on the other hand, try to maximize the overall expected funds they manage. In this paper we prove that, for every market, the DM has an optimal bonus policy such that the firms are motivated to act according to the interests of the DM. On the other hand, we also prove that the only policy that is optimal in every market, is independent of the actions and earnings of the firms.

econ.GN↗