Department of Economics
1805 Cambridge St
Cambridge, MA 02138
Institutional Affiliation: Harvard University
Information about this author at RePEc
NBER Working Papers and Publications
|July 2009||Subgame Perfect Implementation with Almost Perfect Information and the Hold-Up Problem|
with Philippe Aghion, Richard T. Holden: w15167
The foundations of incomplete contracts have been questioned using or extending the subgame perfect implementation approach of Moore and Repullo (1988). We consider the robustness of subgame perfect implementation to the introduction of small amounts of asymmetric information. We show that Moore- Repullo mechanisms may not yield (even approximately) truthful revelation in pure or totally mixed strategies as the amount of asymmetric information goes to zero. Moreover, we argue that a wide class of extensive-form mechanisms are subject to this fragility.
|March 2003||Knife Edge of Plateau: When Do Market Models Tip?|
with Glenn Ellison: w9528
This paper studies whether agents must agglomerate at a single location in a class of models of two-sided interaction. In these models there is an increasing returns effect that favors agglomeration, but also a crowding or market-impact effect that makes agents prefer to be in a market with fewer agents of their own type. We show that such models do not tip in the way the term is commonly used. Instead, they have a broad plateau of equilibria with two active markets, and tipping occurs only when one market is below a critical size threshold. Our assumptions are fairly weak, and are satisfied in Krugman's [1991b] model of labor market pooling, a heterogeneous-agent version of Pagano's  asset market model, and Ellison, Fudenberg and Mobius's  model of competing auctions.
Published: Glenn Ellison & Drew Fudenberg, 2003. "Knife-Edge Or Plateau: When Do Market Models Tip?," The Quarterly Journal of Economics, MIT Press, vol. 118(4), pages 1249-1278, November. citation courtesy of