The paper provides a new formulation of the Mirrlees-Seade theo- rem on the positivity of the optimal marginal income tax, under weaker assumptions and in a more general model. The formulation of the the- orem is independent of whether the model involves finitely many types or a continuous type...

The paper provides a new proof of the positivity of the optimal marginal income tax, in a more general model, under weaker assumptions. The analysis focusses on the (weakly) relaxed problem in which upward incentive constraints are replaced by a monotonicity condition on consumption. Without...

For the standard specification of the utilitarian optimal income tax problem with hidden characteristics, the paper shows that randomized tax schemes are undesirable if preferences exhibit a property of weakly decreasing risk aversion according to the multidimensional risk aversion concept of...