  In this work we study a dynamics of tax evasion. We considered a
fully-connected population divided in three compartments, namely honest tax
payers, tax evaders and susceptibles, a class that is composed by honest tax
payers that can become evaders. We consider a contagion model where the
transitions among the compartments are governed by probabilities. Such
probabilities represent the possible interactions among the indiviudals, as
well as the government's fiscalization. We show by analytical and numerical
calculations that the emergence of tax evaders in the population is associated
with an active-absorbing nonequilibrium first-order phase transition. In the
absorbing phase only honest tax payers survive in the steady states of the
model, and we observe a coexistence of the three subpopulations in the active
phase.
