Biodiversity is often adversely affected by human activities. This reduces social welfare but may be external to private economic decisions. Consequently, these external effects on biodiversity need to be considered explicitly in economic models, which is only partly reflected in the literature....

Optimal harvesting of prey in a predator–prey ecosystem is studied under the condition that the existence of the predator has value. Predators (birds) and humans (fishers) compete for prey (shellfish). The behavior of the system is studied and conditions for optimal control are deduced....

We analyze how the threat of a potential future regime shift affects optimal management. We use a simple general growth model to analyze four cases that involve combinations of stock collapse versus changes in system dynamics, and exogenous versus endogenous probabilities of regime shift. Prior...

We incorporate a renewable resource into an overlapping generations model with standard, well-behaved utility and constant returns production functions. Besides being a factor of production the resource serves as a store of value. We characterize dynamics, efficiency and stability of steady...

We analyze optimal harvesting policy under stochastic price and stock dynamics. We state a set of weak conditions under which the optimal policy can be characterized by a single exercise threshold and show that the value of optimal harvesting and depletion policies can be expressed as the...

The paper develops a version of Pontryagin's maximum principle for optimal control problems with monotonicity constraints on control variables. Whereas the literature handles such constraints by imposing an assumption of piecewise smoothness on the control variable and treating the slope of this...

In this paper we analyze disinflation policy when a central bank has imperfect information about private sector inflation expectations but learns about them from economic outcomes, which are in part the result of the disinflation policy. The form of uncertainty is manifested as uncertainty about...

We solve an optimal growth model in continuous space, continuous and bounded time. The optimizer chooses the optimal trajectories of capital and consumption across space and time by maximizing an objective function with both space and time discounting. We extract the corresponding Pontryagin...

We study optimal experimentation by a monopolistic platform in a two-sided market framework. The platform provider faces uncertainty about the strength of the externality each side is exerting on the other. It maximizes the expected present value of its profit stream in a continuous-time...

This essay studies the optimal timing for a firm to adopt a new process innovation in the presence of learning. A policy that has been implemented by governments throughout the world to reduce the cost level of infant industries with positive externalities, is to either subsidize the research of...