Dear all, the DFG Research Unit ADYN invites you to their next online seminar session on Zoom: *Monday, May 26th, 15:30 CEST*. Link: https://rwth.zoom-x.de/j/68837156442?pwd=H4OW7bUYYAMXSPiqvxXuEMuTTmk7VY.1 Meeting-ID: 688 3715 6442 Kenncode: 593098 The following talks will be given: (1) "Prophet Inequalities with Minimal Priors" by Rebecca Reiffenhäuser (University of Amsterdam) (2) "Persuading Agents in Opinion Formation Games" by Tim Koglin (RWTH Aachen University) Abstracts: (1) Prophet Inequalities are a well-established paradigm in online optimization, but require knowledge of exact prior distributions. The talk will introduce and give an overview on some results that instead run on only a single sample per distribution, still achieving comparable, constant ratios. (2) Prominent opinion formation models such as the one by Friedkin and Johnsen (FJ) concentrate on the effects of peer pressure on public opinions. In practice, opinion formation is also based on information about the state of the world and persuasion efforts. In this talk, we will present an approach of Bayesian persuasion in the FJ model. There is an unknown state of the world that influences the internal beliefs of n agents. A sender S can (partially) reveal information about the state to all agents. The agents update their internal beliefs, and an equilibrium of public opinions emerges. We propose algorithms for the sender to reveal information in order to optimize various aspects of the emerging equilibrium. We will focus on a general class of range-based objectives based on desired opinion ranges for each agent. We will present efficient algorithms for the case that the matrix of internal beliefs in all states has constant rank. This generalizes, e.g., instances with a constant number of states and/or agents. This is joint work with Martin Hoefer and Tolga Tel. For more information on ADYN and the seminar series, visit our website using the link https://adyn.informatik.rwth-aachen.de/ . Best, Tim