Description: While in the familiar problem of optimal commodity taxation the government faces a constraint on tax revenue, we consider the case of a consumption target on a group of commodities (i.e.,a weak constraint on total consumption), instead. This optimal commodity tax problem with a consumption target brings about taxation rules that are mainly at variance with the standard results of commodity taxation. In our main theorem, we derive a general, though quite simple, rule of optimal commodity taxation under a target on total consumption: in particular, we establish that higher consumer prices should be charged for commodities with (1) high price elasticities of total demand and (2) low consumption shares in total demand. From this theorem we deduce three important corollaries: an anti-inverse elasticity result, an anti-Corlett– Hague result and a uniform-pricing result. All of these results are (generically) at variance with well-known rules of commodity taxation.

Description: We examine the effect of simultaneous price changes on the total demand for a group of goods, which we call a compound commodity. Specifically, we consider unit and proportional cost components (e.g., taxes, transportation costs) imposed on compound commodities. If the unit cost is positive, the proportional cost raises the relative price of the more expensive good and thus induces substitution towards the less expensive good within this group. Then, the substitution effect of the proportional cost for a compound commodity is non‐negative if and only if the compound commodity and the other goods are ‘on average’ not strongly substitutable.

Description: In many spatial resource models, it is assumed that an agent is able to harvest the resource over the complete spatial domain. However, agents frequently only have access to a resource at particular locations at which a moving biomass, such as fish or game, may be caught or hunted. Here, we analyze an infinite time‐horizon optimal control problem with boundary harvesting and (systems of) parabolic partial differential equations as state dynamics. We formally derive the associated canonical system, consisting of a forward–backward diffusion system with boundary controls, and numerically compute the canonical steady states and the optimal time‐dependent paths, and their dependence on parameters. We start with some one‐species fishing models, and then extend the analysis to a predator–prey model of the Lotka–Volterra type. The models are rather generic, and our methods are quite general, and thus should be applicable to large classes of structurally similar bioeconomic problems with boundary controls. Recommedations for Resource Managers Just like ordinary differential equation‐constrained (optimal) control problems and distributed partial differential equation (PDE) constrained control problems, boundary control problems with PDE state dynamics may be formally treated by the Pontryagin's maximum principle or canonical system formalism (state and adjoint PDEs). These problems may have multiple (locally) optimal solutions; a first overview of suitable choices can be obtained by identifying canonical steady states. The computation of canonical paths toward some optimal steady state yields temporal information about the optimal harvesting, possibly including waiting time behavior for the stock to recover from a low‐stock initial state, and nonmonotonic (in time) harvesting efforts. Multispecies fishery models may lead to asymmetric effects; for instance, it may be optimal to capture a predator species to protect the prey, even for high costs and low market values of the predators.

Description: In standard models of spatial harvesting, a resource is distributed over a continuous domain with an agent who may harvest everywhere all the time. For some cases though (e.g., fruits, mushrooms, algae), it is more realistic to assume that the resource is located at a fixed point within that domain so that an agent has to travel in order to be able to harvest. This creates a combined travelling–and–harvesting problem where slower travel implies a lower travelling cost and, due to a later arrival, a higher abundance of the resource at the beginning of the harvesting period; this, though, has to be traded off against less time left for harvesting, given a fixed planning horizon. Possible bounds on the controls render the problem even more intricate. We scrutinise this bioeconomic setting using a two-stage optimal control approach, and find that the agent economises on the travelling cost and thus avoids to arrive at the location of the resource too early. More specifically, the agent adjusts the travelling time so as to be able to harvest with maximum intensity at the beginning and the end of the harvesting period, but may also find it optimal to harvest at a sustainable level, where the harvesting and the growth rate of the stock coincide, in an intermediate time interval.

Description: We study the economic management of a renewable resource, the stock of which is spatially distributed and moves over a discrete or continuous spatial domain. In contrast to standard harvesting models where the agent can control the take-out from the stock, we consider the case of optimal stock enhancement. In other words, we model an agent who is, either because of ecological concerns or because of economic incentives, interested in the conservation and enhancement of the abundance of the resource, and who may foster its growth by some costly stock–enhancement activity (e.g., cultivation, breeding, fertilizing, or nourishment). By investigating the optimal control problem with infinite time horizon in both spatially discrete and spatially continuous (1D and 2D) domains, we show that the optimal stock–enhancement policy may feature spatially heterogeneous (or patterned) steady states. We numerically compute the global bifurcation structure and optimal time-dependent paths to govern the system from some initial state to a patterned optimal steady state. Our findings extend the previous results on patterned optimal control to a class of ecological systems with important ecological applications, such as the optimal design of restoration areas.

Description: We consider an optimal commodity taxation problem under a consumption target and prove the existence of an optimal solution for the problem. This optimal solution obeys taxation rules that are contrary to standard taxation rules such as the inverse-elasticity rule. We also verify the necessary and sufficient condition for the optimal solution to exhibit uniform pricing.

Description: This paper contributes to the analysis of centralised versus decentralised labour market negotiations. Applying the familiar Nash bargaining solution, we show that centralised negotiations lead to a lower employment level but to a higher wage rate than decentralised labour market bargaining. While this is an important theoretical result on its own, it has important effects for both empirical labour market research and labour market policies. Also, this result counters the critique that efficient negotiations result in employment levels exceeding the competitive level.

Description: The presence of tipping points in ecological systems implies abrupt changes in the dynamics of the ecosystem. In these piecewise-smooth dynamical systems sliding dynamics, i.e., dynamics on the switching boundary, have been reported for population models. However, the question whether or not, and if so under which conditions, sliding dynamics may occur in an optimally controlled system have not yet been studied. We explore this issue in a simple harvesting model with two regimes, and find that optimal sliding may occur if regular steady states do not exist. Hence, sliding dynamics may be part of an optimal policy.