Archives 2023-2024

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : Minimising externalities ex ante and mechanism design

Summary: We revisit in the fair division context the fundamental normative trade-off between the liberal (Coasian) resolution of interpersonal externalities by decentralised person to person negotiations, apt to discover new unforeseen solutions and promote cooperation; and the regulated approach under the rule of a centrally designed mechanism, completely eliminating unscripted interactions.

At the ex ante stage where the other agents' characteristics are unknown, the difference in welfare between my worst and best cases scenarios is the extent of interpersonal externalities I can be subject to. As a solution of the normative trade-off above we submit that the role of the mechanism designer should be limited to the minimisation of this gap.

Maximising the worst case welfare, discussed first in mathematical cake-cutting stories more than 75 years ago is probably the simplest and most versatile normative principle in fair division. Minimising the best case welfare is an equally legitimate concern. It is not spiteful when the eventual outcome is efficient: allowing you higher potential gains ex ante must reduce those of some other agent(s).

In most fair division problems, the designer can choose from a menu of maximal lower guarantees (my worst case welfare as a function of my characteristics) and/or minimal upper guarantees. Discovering these menus is a hard mathematical question, even in many simple instances. We do it in two iconic examples: the commons problem with homogenous inputs and outputs, and the allocation of indivisible goods (or bads) with transfers. Thre results confirm the prominence of some familiar division rules and discover new ones.

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : Welfare vs. choice-theoretic utility

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : TBA

Summary:  TBA

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : TBA

Summary:  TBA

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : Prerationality in Enlivened Decision Trees

Summary:  In principle a decision-making agent's possible decisions and their uncertain consequences can be modelled and formally analysed using a decision tree. Yet except in relatively trivial cases, practicality puts bounds on the size and complexity of any tree that can be analysed properly. When the agent faces a sequence of decisions, the decision tree that the agent analyses may become "enlivened" between successive decisions by the addition of new nodes and new branches, possibly involving extensions to the set of states of the world, as well as enrichments of the consequence domain. My talk will first illustrate the concept of an enlivened decison tree by means of examples involving: (i) Homer's tale of Odysseus and the Sirens; (ii) José Luis Borges' "El Aleph", as a literary example of an unbounded model of the universe; (iii) births, marriages, and deaths; (iv) in economics, the related concepts of innovation and entrepreneurship in Joseph Schumpeter's 1911 "Theory of Economic Development"; (v) in decision theory, George Shackle's concept of “unexpected events”, as well as Nassim Nicholas Taleb's of a "true" black swan, and the work of John Kay and Mervyn King on radical uncertainty; (vi) the games of Go and Chess. Nevertheless, one can model uncertainty about the ultimate retrospective value of any decision that the agent might make within whatever tree captures the current level of awareness. This allows the arguments of consequentialist decision theory that imply subjective expected utility maximization to be extended from standard to enlivened decision trees. 

Friday,  December 1st   Gaëtan Fournier  (Aix-Marseille School of Economics) 

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title :  Turnout in spatial competition

Summary: 

Abstract: We examine two public policies aimed at increasing voter turnout in electoral spatial competition: reducing the cost of voting and modifying the financial incentives provided to parties. We find that these policies have different and disjoint impacts, when one is efficient, the other does not affect turnout. We characterize the voters' characteristics under which each policy is effective. 

January 19th,   Patrick Lahr   (ENS-Paris Saclay) 

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : On the Geometry of Multi- Dimensional Screening


Summary : Extreme points of the set of implementable allocations are tied to the two central questions of mechanism design: What can be implemented, and what is optimal? We characterize the extreme points within a linear, multi-dimensional screening model. Our characterization links mechanism design to Gale’s (1954) theory of indecomposable convex bodies. Whenever the type space is one-dimensional, extreme points are simple, never requiring a larger menu size than under the agent’s first best. In stark contrast with a multi-dimensional type space any IC mechanism exhausting a maximal set of feasibility constraints is arbitrarily close to an extreme point. This conclusion is obtained even when considering only those extreme points that are maximizers of specific classes of objective functionals, such as revenue. Our conclusions apply to monopolistic selling, finite delegation, and veto bargaining.

January 26th,   Sudipta Sarangi    (Virginia Tech) 

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : TBA

Summary : TBA

February  16th,   Jobst Heitzig (Potsdam Institute for Climate Impact Research)

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Title : TBA

March 15th :Sylvain Carré (Université Paris Dauphine)

Title : Security and efficiency in DeFi lending

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Summary : 

March 22nd :Jean-Yves Gnabo, Université de Namur 

Title : TBA

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Summary : TBA

March 29th :David Frankel (Melbourne business school)

Title : TBA 

Location and time: Maison des Sciences Économiques, S17 , 12-13h

Summary : TBA