• December 1, 2025 (room Maryam Mirzakhani): Antonin MACE (PSE) Repeated Majority Voting, with Rafael Treibich.

Abstract : We propose a general model of repeated voting in committees and study equilibrium behavior under alternative majority rules. We find that repetition may significantly increase the efficiency of majority voting through a mechanism of intertemporal logrolling, agents sometimes voting against their immediate preference to benefit the group’s long-term interest. In turn, this affects the comparison of majority rules, which may differ significantly relative to the static setting. The model provides a rationale for the use of super-majority rules, while accounting for the prevalence of consensus in committee voting.

• December 8, 2025 (room Maryam Mirzakhani): Claire MATHIEU (CNRS)

• December 15, 2025 (room Pierre Grisvard): Jean-Pierre PONSSARD (CNRS,  Ecole Polytechnique) Imperfect Competition and the Adoption of Clean Technology: The Case of CCS in Cement

• December 22, 2025: No seminar

• December 29, 2025: No seminar

• January 5, 2025 (room Maryam Mirzakhani): TBA

• January 12, 2025 (room Pierre Grisvard) :  Bertrand CRETTEZ (Pantheon Assas University) On the Existence of Coalitional Berge Equilibrium in Discontinuous Games

We study the existence coalitional Berge equilibria in games that may be discontinuous. We introduce a new notion of continuity, called weak mutual transfer quasi-continuity, which is weaker than most known notions of transfer continuity, including diagonal transfer continuity, and which holds in a large class of discontinuous games. We show that when a compact and convex game satisfies the weak mutual transfer quasi-continuity property, there exists a pure strategy coalitional Berge equilibrium if, and only if, the game satisfies a strong mutual transfer quasic-oncavity property, which we also introduce in the paper. Furthermore, we give sufficient conditions for weak mutual transfer quasi-continuity and we provide characterizations of mixed strategy coalitional Berge equilibria in discontinuous games.

• January 19, 2025 (room Maryam Mirzakhani): Martin VAETH (PSE)

• January 26, 2025 (room Maryam Mirzakhani): Lu YU (ENPC) "Fixed point theorems for correspondences and Nash equilibria of games with complementarities."

• February 2, 2025 (room Maryam Mirzakhani :  (double seminar) Bary Pradleski (CNRS): 10h-11h, and Jörgen Weibull (Stockholm School of Economics): 11h-12h

• February 9, 2025 (room Pierre Grisvard): TBA

• February 16, 2025 (room Maryam Mirzakhani): Naïla HAYEK (Panthéon Assas Université)

• February 23, 2025: No seminar

• March 2, 2025: No seminar

• March 9, 2025 (room Pierre Grisvard): TBA

• March 16, 2025 (room Maryam Mirzakhani): TBA

• March 23, 2025 (room Maryam Mirzakhani): TBA

• March 30, 2025 (room Pierre Grisvard): Angelo FANELLI (LAMSADE, Université Paris-Dauphine)

• April 6, 2025: No seminar

• April 13, 2025 (room Maryam Mirzakhani): Julien COMBE (CREST, Ecole polytechnique)

• April 20, 2025: No seminar

• April 27, 2025:  No seminar

• May 4, 2025 (room Pierre Grisvard): TBA

• May 11, 2025 (room Maryam Mirzakhani): TBA

• May 18, 2025(room Maryam Mirzakhani) : TBA

• May 25, 2025: No seminar

• June 1, 2025 (room Pierre Grisvard): TBA

• June 8, 2025: (room Maryam Mirzakhani) TBA

• June 15, 2025 (room Maryam Mirzakhani): TBA

• June 22, 2025 (room Maryam Mirzakhani): TBA

• June 29, 2025 (room Maryam Mirzakhani): TBA