  The addition of wealth-attained advantage (WAA) to the Yard-Sale Model (YSM)
of asset exchange has been demonstrated to induce wealth condensation. In a
model of WAA for which the bias is a continuous function of the wealth
difference of the transacting agents, the condensation was shown to arise from
a second-order phase transition to a coexistence regime. In this paper, we
present the first analytic time-dependent results for this model, by showing
that the condensed wealth obeys a logistic equation in time.
