Help the low skilled or let the hardworking thrive? A study of fairness in optimal income taxation

In a model where agents have unequal wages and heterogeneous preferences, we study the optimal redistribution via an income tax, when the social objective is based on a combination of efficiency and fairness principles, and when incentive issues are taken into account. We show how some fairness principles entail specific features for the optimal taxes, such as progressivity or tax exemption for incomes below the minimum wage.