Conference announcement: 30 Years of Game Theory at Institut Henri Poincaré, October 06-10, 2025, Paris.

Welcome

The Séminaire parisien de Théorie des Jeux is an open, inter-institutional, multi-disciplined seminar which covers all fields of game theory. It takes place on Monday from 11:00 to 12:00 am at Institut Henri Poincaré, 11 rue Pierre et Marie Curie, Paris 5ème. MAP

You will find the program for the current academic year on the page 2025/2026 and the program for past years on the page Archives.

The junior seminar welcomes PhD students in game theory to present their work.  You will find the program for the current academic year on the page Junior Seminar 2025/2026.

Next seminar:  

December 15, 2025 (room Pierre Grisvard): 

Jean-Pierre PONSSARD (CNRS,  Ecole Polytechnique) 

will present : Imperfect Competition and the Adoption of Clean Technology: The Case of CCS in Cement with Quentin Hoarau

Abstract : This paper studies the adoption of clean technology in an oligopolistic setting, focusing on carbon capture and storage (CCS) in the cement sector. Firms can choose between two technologies: a carbon-intensive ("dirty") technology and a low-carbon ("clean") one. Initially, all firms operate with the dirty technology, whose variable cost increases over time with the social cost of carbon, following Hotelling's rule. Clean technology has a constant marginal cost but requires a sunk investment cost. Firms engage in short-term Cournot competition, and the adoption decision is modeled as a dynamic continuous time game. We show that imperfect competition leads to inefficiently delayed adoption due to preemption incentives, with firms eventually coordinating on a late joint adoption equilibrium. We propose two corrective public policies: a fixed-cost subsidy and a time-dependent subsidy on profit flows. Calibrating our model to the cement industry, assuming five competitors, we find that without policy intervention, CCS adoption would occur in 2042 rather than the socially optimal date of 2030. Obtaining optimal timing requires either a 70% fixed-cost subsidy or a time-dependent subsidy equivalent to 20% of that amount, although it requires more information for implementation.

Organizers

Frédéric Koessler (CNRS, HEC Paris), frederic.koessler[at]gmail[dot]com

Maël Letreust  (CNRS,  IRISA Rennes), mael.le-treust[at]cnrs[dot]fr

Chantal Marlats (LEMMA, Université Paris Panthéon-Assas), chantal.marlats[at]u-paris2[dot]fr

Yannick Viossat (CEREMADE, PSL), viossat[at]ceremade[dot]dauphine[dot]fr

To join (or unsuscribe from) our mailing list, please contact Chantal Marlats at chantal.marlats[at]assas-universite[dot]fr. 

Former organizers

Joseph Abdou; Bernard De Meyer; Françoise Forges; Olivier Gossner;  Marie Laclau; Rida Laraki; Lucie Ménager; Vianney Perchet; Jérôme Renault; Dinah Rosenberg; Sylvain Sorin; Tristan Tomala; Xavier Venel; Nicolas Vieille; Guillaume Vigeral; Bruno Ziliotto