We consider the problem of regulating a monopolist with unknown costs when the regulator has limited funds. The optimal regulatory mechanism satisfies four properties. The first property is bunching at the top, that is the more efficient types produce the same quantity irrespective of their...

We present an alternative proof of Fishburn’s (1975) axiomatization of lexicographic preferences. The essence of our proof lies in identifying “an extremely pivotal factor”. Our proof reconfirms the strong interconnections between Arrow’s and Gibbard–Satterthwaite’s theorems with...

We investigate the implications of egalitarian equivalence (Pazner and Schmeidler in Q J Econ 92:671–687, <CitationRef CitationID="CR31">1978</CitationRef>) together with queue efficiency and strategyproofness in the context of queueing problems. We completely characterize the class of mechanisms satisfying the three requirements. Though...</citationref>

We revisit the classic comparison between Bertrand and Cournot outcomes in a mixed market with private and public firms. The results are often strikingly different and opposite to the ones obtained from a similar comparison in the standard setting with all profit-maximizing firms.

We identify and characterize a natural and intuitive class of mechanisms called the k-pivotal mechanisms. The axioms used are efficiency, pairwise strategyproofness, equal treatment of equals and weak linearity. We also identify the subclass of these mechanisms which do not run a budget deficit...

We revisit the comparison between Bertrand and Cournot competition in a symmetric differentiated oligopoly where each firm maximizes a weighted average of its own profit and welfare. Under very general specifications, Bertrand competition yields higher prices and profits, and lower quantities,...

Subgroup additivity requires that a rule assigns the same expected ‘relative’ utility to each agent whether an agent’s expected relative utility is calculated from the problem involving all agents or from its sub-problems with a smaller number of agents. In this paper, we investigate its...