Gini index, inequality comparisons and maximin axiom: a paradox

Inequality is appreciated only through a relevant measure, traditionally the Gini index, but this one presents a weakness that prevents to consider it as valid: to a same Gini may correspond many distributions. For the most simple case, a concentration curve with two linear segments, a criterion is proposed, based on the maximin: beside curves with same Gini, the more egalitarian is those in which each poor has the higher revenue. However, this does not allow to decide for two curves with different Gini: two indeterminate zones appear. This is extended to curves with three linear segments and two kinks. Keywords : Gini; maximin; Lorenz; concentration; inequality