16h00–17h00 — Salle du conseil (L2S)
Indecision-breaking in multi-agent, multi-option opinion dynamics: a symmetry perspective
Alessio Franci (Univ. Liège, Belgium)
Abstract. How does a group of agents break indecision when deciding about options with qualities that are hard to distinguish? Biological and artificial multi-agent systems, from honeybees and bird flocks to bacteria, robots, and humans, often need to overcome indecision when choosing among options in situations in which the performance or even the survival of the group are at stake. Breaking indecision is also important because in a fully indecisive state agents are not biased toward any specific option and therefore the agent group is maximally sensitive and prone to adapt to inputs and changes in its environment. Here, we develop a mathematical theory to study how decisions arise from the breaking of indecision. Our approach is grounded in both equivariant and network bifurcation theory. We model decision from indecision as synchrony-breaking in influence networks in which each node is the value assigned by an agent to an option and show that three universal decision behaviors, namely, deadlock, consensus, and dissensus, are the generic outcomes of synchrony-breaking bifurcations from a fully synchronous state of indecision in opinion networks. Inspired by these model-independent results, we introduce a new nonlinear model of opinion dynamics over networks and illustrate its value for understanding flexible and tunable decision-making in a wide variety of contexts.
Biography. Alessio Franci got his Master 2 (Laurea Specialistica) Degree in Theoretical Physics from the University of Pisa in 2008 and his PhD in Physics and Control Theory from the University of Paris Sud 11 in 2012. Between 2012 and 2015 he was a postdoctoral researcher at the University of Liege and at INRIA Lille. Between 2013 and 2015 he was also a long term visiting researcher at the University of Cambridge. Between 2015 and 2022 he was professor in the Math Department of UNAM – National Autonomous University of Mexico. Since 2023 he has been professor in the Department of Electrical Engineering and Computer Science of the University of Liege.
His research interests span different fields but the central focus is on the control-theoretical and computational principles of biological and bio-inspired behaviors like excitable neuronal behavior, collective decision making, and neuromorphic computing. Thanks to local and international collaborations, his research has a strong interdisciplinary inclination.
