  We present here a general framework, expressed by a system of nonlinear
differential equations, suitable for the modelling of taxation and
redistribution in a closed (trading market) society. This framework allows to
describe the evolution of the income distribution over the population and to
explain the emergence of collective features based on the knowledge of the
individual interactions. By making different choices of the framework
parameters, we construct different models, whose long-time behavior is then
investigated. Asymptotic stationary distributions are found, which enjoy
similar properties as those observed in empirical distributions. In particular,
they exhibit power law tails of Pareto type and their Lorenz curves and Gini
indices are consistent with some real world ones.
