Seminario: Impartial selection
4 de Noviembre, 2025
El Instituto de Ingeniería Matemática y Computacional (IMC) invita al seminario que se dictará este miércoles 12 de noviembre.
Javier Cembrano, Algorithms and Complexity Department, Max Planck Institute for Informatics
Miércoles 12 de noviembre de 2025, 13:40 hrs. (Presencial en auditorio Edificio San Agustín. Link Zoom disponible escribiendo a imc@uc.cl)
ABSTRACT
Impartial selection addresses the problem of choosing one or more agents from a group based on nominations by other members of the group, in such a way that no agent can influence their own chance of being selected.
Deterministic mechanisms for selecting a single agent face strong impossibilities. For example, Holzman and Moulin (Econometrica, 2013) showed that when each agent nominates one other agent, no impartial mechanism can simultaneously satisfy positive unanimity—that an agent nominated by everyone else is selected—and negative unanimity—that an agent with no nominations is not selected. In response to such negative results, subsequent work has explored relaxations of this setting, either by allowing randomization or by permitting the selection of a variable number of agents. In this talk, we will further motivate these relaxations by presenting a strengthening of Holzman and Moulin’s impossibility for the case where agents may nominate any number of peers, and we will cover some recent results on both relaxations. We will also discuss how the performance of impartial mechanisms can be improved if a prediction of the optimal set of agents is available.
BIO
Javier Cembrano is a postdoctoral researcher at the Max Planck Institute for Informatics, currently in a visiting position at Universidad de Chile. Previously, he graduated as an industrial engineer and MS in Operations Management at Universidad de Chile, and obtained a PhD in Mathematics at TU Berlin. His main research interests lie in the intersection of economics, mathematics, and computer science, particularly in the areas of algorithmic game theory and computational social choice.
