We put forward a model of private goods with externalities. Agents derive benefit from communicating with each other. In order to communicate they need to have a language in common. Learning languages is costly. In this setting no individually rational and feasible Groves mechanism exists. We...

This note explains the equivalence between approximate rationalizability and approximate cost-rationalizability within the context of consumer demand. In connection with these results, we interpret Afriat’s (1973) critical cost efficiency index (CCEI) as a measure of cost (in)efficiency, in...

In actual environmental policy, the design of actual pollution emission taxes differs significantly with the optimal Pigovian tax. In particular, earmarking prevails and actual taxes are usually combined with regulation. Furthermore tax rates are generally too low to significantly influence...