Monotonicity and the Pareto Principle

The property of monotonicity, th criterion of (first-degree) income dominance and the Pareto principle appear frequently in the literature on the axiomatic approach to the welfare economics of income distribution. Sometimes these are regarded as almost interchangeable for practical purposes. However, as we shall show, this interchangeability arises because of other important assumptions that are also commonly invoked, but which may be questionable.