We examine the possibilities of extending Sen's taxonomy of fixed-population information assumptions regarding the measurability and interpersonal comparability of individual utilities to social-choice problems where the population may vary. It is shown that in order to avoid impossibility...

Comparative static properties of the solution to an optimal nonlinear income tax problem are provided for a model in which the government both designs an income tax schedule for redistributive purposes and provides a public good optimally. There are two types of individuals, distinguished by...