Séminaires

Date: 20/03/2026 à 11h30 Lieu: Salle C057 Titre: Learning in Proportional Allocation Auctions Games Résumé : The Kelly or proportional allocation mechanism is a simple and efficient auction-based scheme that distributes an infinitely divisible resource proportionally to the agents’ bids. When agents are aware of the allocation rule, their interactions form a game, that has been extensively studied. This paper examines the less explored repeated Kelly game, focusing mainly on utilities that are logarithmic in the allocated resource fraction. We first derive this logarithmic form from fairness–throughput trade-offs in wireless network slicing, and then prove that the induced stage game admits a unique Nash equilibrium (NE). For the repeated play, we prove convergence to this NE under three behavioral models: (i) all agents use Online Gradient Descent (OGD), (ii) all agents use Dual Averaging with a quadratic regularizer (DAQ) (a variant of the Follow-the-Regularized leader algorithm), and (iii) all agents play myopic best responses (BR). Our convergence results hold even when agents use personalized learning rates in OGD and DAQ (e.g., tuned to optimize individual regret bounds), and they extend to a broader class of utilities that meet a certain sufficient condition. Finally, we complement our theoretical results with extensive Plus d'infos

Vendredi 27 Février à 11h30 en C057. Title: Games with Rational and Herding Players Résumé : This talk examines large-population games with heterogeneous decision-making, in which an α-fraction of players are rational, while the remaining agents exhibit herding behaviour. We introduce a new equilibrium notion, called the α-Rational Nash Equilibrium (α-RNE), and discuss its interpretations. We show that some classical equilibria may disappear and new ones may emerge for small values of α>0. Interestingly, rational players benefit from the presence of herding and may even achieve utility exceeding the socially optimum. Even more strikingly, in some cases, herding players also benefit, attaining utility close to the social optimum. Using transportation and bandwidth sharing games as case studies, we analyse the impact of herding on congestion and resource allocation, and quantify system inefficiencies through the Price of Anarchy. Finally, we discuss the mechanism and influence design in the presence of herding. While the expanded set of equilibria creates new opportunities, it also increases the risk of undesirable outcomes when influence cannot be effectively implemented.

    Vendredi 14 novembre, 11h30 – Salle C057. Title: Multi-Agent Reinforcement Learning for Task Offloading in Wireless Edge Networks Abstract: In edge computing systems, autonomous agents must make rapid local decisions while competing for shared resources. Existing MARL approaches often rely on centralized critics or frequent inter-agent communication, which breaks down under limited observability and communication constraints. We propose a decentralized framework in which agents coordinate implicitly through a shared constraint on resource usage. This constraint is updated infrequently, requiring minimal communication, while each agent independently solves a local constrained Markov decision process (CMDP) to learn its behavior. Leveraging safe reinforcement learning, agents learn policies that satisfy both local and global objectives. We provide theoretical guarantees under mild assumptions and validate our approach experimentally, demonstrating superior performance to centralized and independent baselines, particularly in large-scale settings.

20 Novembre 2025 – 11h30 – Salle C057.   Titre : Strategic Analysis of Just-In-Time Liquidity Provision in Concentrated Liquidity Market Makers   Abstract: Liquidity providers (LPs) are essential figures in the operation of automated market makers (AMMs); in exchange for transaction fees, LPs lend the liquidity that allows AMMs to operate. While many prior works have studied the incentive structures of LPs in general, we currently lack a principled understanding of a special class of LPs known as Just-In-Time (JIT) LPs. These are strategic agents who momentarily supply liquidity for a single swap, in an attempt to extract disproportionately high fees relative to the remaining passive LPs. This paper provides the first formal, transaction-level model of JIT liquidity provision for a widespread class of AMMs known as Concentrated Liquidity Market Makers (CLMMs), as seen in Uniswap V3, for instance. We characterize the landscape of price impact and fee allocation in these systems, formulate and analyze a non-linear optimization problem faced by JIT LPs, and prove the existence of an optimal strategy. By fitting our optimal solution for JIT LPs to real-world CLMMs, we observe that in liquidity pools (particularly those with risky assets), there is a significant gap between observed Plus d'infos

Nous avons le plaisir de vous inviter au séminaire de l’équipe CORNET, qui se tiendra le jeudi 5 juin à 11h35 en salle C057 (ancienne BU). À cette occasion, nous accueillerons Cléophée Robin, enseignante-chercheuse à l’IRIF, qui nous présentera ses travaux intitulés : _________________________________________________________ Clique-covering co-bridge-free prismatic graphs Résumé : A graph G is prismatic if for every triangle T of G, every vertex of G that is not in T, has exactly one neighbor in T. The complement of a prismatic graph is called antiprismatic. The complexity of the coloring problem when restricted to prismatic graphs is unknown. Hence, the complexity of the clique-covering problem on prismatic graphs is also unknown. Chudnovsky and Seymour gave a full structural description of prismatic graphs. They divided the class in two subclasses : the orientable prismatic graphs and the non-orientable prismatic graphs.  Preissman, Robin and Trotignon gave an algorithm to solve the clique problem in non-orientable prismatic graphs in polynomial time. We show this algorithm can also be used for prismatic graphs with no 2K_1 + C_4 (co-bridge), whether they are orientable or not. To achieve this, we show that this class of graphs admits a bounded number of disjoint triangles through Plus d'infos

Dans le cadre de séminaires de l’équipe CORNET,  nous aurons le plaisird’accueillir M Giuseppe DI MOLFETTA ce lundi 10/03 à 12h00  Salle 6 CERI Titre: Quantum Computing : a gentle introduction Résumé : A short, self-consistent one-hour seminar to introduce quantumcomputing and some simple applications in algorithmics in a non-formalway. No pre-requisites required, the presentation will cater for apotentially heterogeneous audience.