Analysis of state-control optimality system for invasive species management

Mathematical modeling and optimization provide decision-support tools of increasing popularity to the management of invasive species. In this paper we investigate problems formulated in terms of optimal control theory. A free terminal time optimal control problem is considered for minimizing the costs and the duration of an abatement program. Here we introduce a discount term in the objective function that destroys the non-autonomous nature of the state-costate system. We show that the alternative state-control optimality system is autonomous and its analysis provides the complete qualitative description of the dynamics of the discounted optimal control problem. By using the expression of its invariant we deduce several insights for detecting the optimal control solution for an invasive species obeying a logistic growth.