He is currently the Chaired Professor of Economic Theory and Social Organization of the Collège de France, Director of Studies at the École des hautes études en sciences sociales, and the chairman of the board of directors of the Paris School of Economics.
He has taught at the London School of Economics, the École Polytechnique, and at Harvard University.
"Starting with a paper in Econometrica by Dierker, Guesnerie and Neuefeind (1985), a theory of general equilibrium has developed for economies with non-convex production sets, where firms follow well-defined pricing rules.
In particular, existence theorems of increasing generality cover (to some extent, because of various differences in assumptions) the case of Ramsey-Boiteux pricing.
Those interested primarily in applications might express skepticism, perhaps even horrified skepticism, upon realizing that 90 pages of a serious economics journal—a 1988 issue of The Journal of Mathematical Economics—were devoted to existence proofs of equilibrium in non-convex economies, under alternative formulations of the assumption that marginal cost pricing entails bounded losses at normalized prices.