Single--crossover recombination in discrete time

Modelling the process of recombination leads to a large coupled nonlinear dynamical system. Here, we consider a particular case of recombination in {\em discrete} time, allowing only for {\em single crossovers}. While the analogous dynamics in {\em continuous} time admits a closed solution, this no longer works for discrete time. A more general model (i.e. without the restriction to single crossovers) has been studied before and was solved algorithmically by means of Haldane linearisation. Using the special formalism introduced by Baake and Baake (2003), we obtain further insight into the single-crossover dynamics and the particular difficulties that arise in discrete time. We then transform the equations to a solvable system in a two-step procedure: linearisation followed by diagonalisation. Still, the coefficients of the second step must be determined in a recursive manner, but once this is done for a given system, they allow for an explicit solution valid for all times.Comment: J. Math. Biol., in pres

Consumer-Optimal Information Design

In many trade environments - such as online markets - buyers fully learn their valuation for goods only after contracting. I characterize the buyer-optimal ex-ante information in such environments. Employing a classical sequential screening framework, I find that buyers prefer to remain partially uninformed, since such an information structure induces the seller to set low prices. For the optimal information signal, trade is efficient, and the seller only extracts the static monopoly profit. Further, I fully characterize all possible surplus divisions that can arise in sequential screening for a given prior

Persuasion Against Self-Control Problems

I derive a social planner's optimal information design in an environment with quasi-hyperbolic discounting consumers without commitment. Consumption induces instantaneous utility, but unknown delayed cost. Consumers may or may not acquire additional costless information on the cost parameter. The planner's optimal signal can be interpreted as an incentive compatible consumption recommendation whenever the cost parameter is below some cut-off. Welfare strictly exceeds the one under full information. I characterize distributional conditions under which welfare attains first best

Inexpressive Law

According to expressive law theories, expression of values is an important function played by the law. Expressive laws affect behavior, not by threatening sanctions or promising rewards, but by changing individual preferences and tastes and, in some cases, by affecting social norms and values. New laws, however, can run against sticky social norms, failing to achieve their expressive effects. By developing a dynamic model, in this paper we show that inexpressive laws (laws whose expressive function is undermined by sticky norms) can not only be ineffective but can push the values of society away from those expressed by the law. We study the effects of legal intervention on the values shared by members of society, considering the feedback effects between laws and social norms. Just like expressive laws can foster consensus in heterogeneous groups, inexpressive laws can create a social divide, even in previously homogeneous societies.Social Norms, Countervailing Effect, Expressive Law, Civil Disobedience

Beschleunigung von Genehmigungsverfahren

Genehmigungsverfahren, Verwaltungsreform,

Application Costs and the Design of Licensing Procedures

License procedures are a common way of enforcing regulation of activities whose effects on social welfare depend on the specificities of the single case. Building permits may serve as an example, but many other licensing procedures follow the same structure. In particular in Germany, the long duration of such procedures and the low predictability of their outcomes have been identified as a major obstacle to economic progress. As a consequence, the German legislators have invoked legislation to accelerate the procedure. This paper investigates how the acceleration approaches affect not only the costs of citizens who already led an application but also how influence decisions on whether to apply and what projects to plan. I will show that acceleration may have unintended side effects which may more than offset the increase in welfare gained by lower application costs. I will also show that deterrence of applications based on illegal project need not be a better alternative: it may be impossible not to deter the legal projects as well.Regulation, Licensing Procedures, Administration Costs, Over-Deterrence,

Optimal Sequential Investigation Rules in Competition Law

Although both in US antitrust and European competition law there is a clear evolution to a much broader application of "rule of reason" (instead of per-se rules), there is also an increasing awareness of the problems of a case-by-case approach. The "error costs approach" (minimizing the sum of welfare costs of decision errors and administrative costs) allows not only to decide between these two extremes, but also to design optimally differentiated rules (with an optimal depth of investigation) as intermediate solutions between simple per-se rules and a fullscale rule of reason. In this paper we present a decision-theoretic model that can be used as an instrument for deriving optimal rules for a sequential investigation process in competition law. Such a sequential investigation can be interpreted as a step-by-step sorting process into ever smaller subclasses of cases that help to discriminate better between pro- and anticompetitive cases. We analyze both the problem of optimal stopping of the investigation and optimal sequencing of the assessment criteria in an investigation. To illustrate, we show how a more differentiated rule on resale price maintenance could be derived after the rejection of its per-se prohibition by the US Supreme Court in the "Leegin" case 2007.Law Enforcement, Decision-Making, Competition Law, Antitrust Law