Séminaires LEMMA

"Cooperative games with unpaid players"

Léa Munich (Assas-CRED), avec Sylvain Béal, Kevin Techer, Philippe Solal

Léa étudie la résolution de problèmes d’allocation des coûts et des responsabilités en mobilisant la théorie des jeux coopératifs, l’approche normative, la recherche opérationnelle et l’analyse économique du droit.

Monday, 3 February 2026, 11h-12h

Lemma - 4 rue Blaise Desgoffe, 75006 Paris. Salle Maurice Desplas

Abstract : We consider cooperative TU-games with unpaid players, which are described by a TUgame and two categories of players, paid and unpaid. Unpaid players participate in the cooperative game but are not rewarded for their participation, for instance for legal reasons. The objective is then to determine how the contributions of unpaid players are redistributed among the paid players. To meet this goal, we introduce and characterize axiomatically three values that are inspired by the Shapley value but differ in the way they redistribute the contributions of unpaid players. These values are uniffed as instances of a more general two-step allocation procedure.

"After D-day? Destruction, Catch up, and Leapfrog"

Lisa Chauvet (Université Paris 1 Panthéon-Sorbonne), avec Abel François et Jean Lacroix

Lisa is Professor of Economics at the Université Paris 1 Panthéon-Sorbonne. Her research interests include international financing, economic growth, migration, and political economy.

Monday, 27 January 2026, 11h-12h

Lemma - 4 rue Blaise Desgoffe, 75006 Paris. Salle Maurice Desplas

Abstract : How do conflicts shape territories in the long run? To answer this question, this paper dissects population dynamics within Normandy throughout the 20th century. Despite the destruction caused by the 1944 Allied Landings, Normandy reversed the demographic decline it had experienced until 1940 – a dynamic at odds with previous literature showing a negative or neutral effect of conflict on city growth in the long run. Using a difference-in-differences estimator, we confirm that within Normandy, combat duration dampened population growth in the short run. In the medium run, areas exposed to combat recovered and later overshot the population levels implied by their initial trend. An analysis of a comprehensive inventory of all dwelling units 25 years after WW2 suggests that the post-war reconstruction effort explains this counterintuitive result.