Subcritical contact processes seen from a typical infected site

What is the long-time behavior of the law of a contact process started with a single infected site, distributed according to counting measure on the lattice? This question is related to the configuration as seen from a typical infected site and gives rise to the definition of so-called eigenmeasures, which are possibly infinite measures on the set of nonempty configurations that are preserved under the dynamics up to a multiplicative constant. In this paper, we study eigenmeasures of contact processes on general countable groups in the subcritical regime. We prove that in this regime, the process has a unique spatially homogeneous eigenmeasure. As an application, we show that the exponential growth rate is continuously differentiable and strictly decreasing as a function of the recovery rate, and we give a formula for the derivative in terms of the eigenmeasures of the contact process and its dual.Comment: Changed the organization of the proofs somewhat to more clearly make a link to classical results about quasi-invariant laws. 44 page

The costs of remoteness: evidence from German division and reunification

This paper exploits the division of Germany after the Second World War and the reunification of East and West Germany in 1990 as a natural experiment to provide evidence of the importance of market access for economic development. In line with a standard new economic geography model, we find that following division cities in West Germany that were close to the new border between East and West Germany experienced a substantial decline in population growth relative to other West German cities. We provide several pieces of evidence that the decline of the border cities can be entirely accounted for by their loss in market access and is neither driven by differences in industrial structure nor differences in the degree of warrelated destruction. Finally, we also find some first evidence of a recovery of the border cities after the re-unification of East and West Germany

Term Limits and Electoral Accountability

Periodic elections are the main instrument through which voters can hold politicians accountable. From this perspective term limits, which restrict voters' ability to reward politicians with re-election, appear counterproductive. We show that despite the disciplining effect of elections, term limits can be ex ante welfare improving from the perspective of voters. By reducing the value of holding office term limits can induce politicians to implement policies that are closer to their private preferences. Such "truthful" behavior by incumbents in turn results in better screening of incumbents. We show that the combination of these two effects can strictly increase the utility of voters.Political Agency, Accountability, Term Limits

How Elections Matter: Theory and Evidence from Environmental Policy

In this paper we explore to what extent secondary policy issues are influenced by electoral incentives. We develop a political agency model in which a politician decides on both a frontline policy issue, such as the level of public spending, and a secondary policy issue, such as environmental policy. The model shows under which conditions the incumbent finds it worthwhile to manipulate the secondary policy to attract additional votes to his platform. We test the predictions of the model using state-level panel data on Gubernatorial environmental policy choices over the years 1960-2000. In contrast to the popular view that choices on secondary policy instruments are largely determined by lobbying, we find strong effects of electoral incentives on environmental policy.

Political Competition, Policy and Growth: Theory and Evidence from the United States

This paper develops a simple model to analyze how a lack of political competition may lead to policies that hinder economic growth. We test the predictions of the model on panel data for the US states. In these data, we find robust evidence that lack of political competition in a state is associated with anti-growth policies: higher taxes, lower capital spending and a reduced likelihood of using right-to-work laws. We also document a strong link between low political competition and low income growth.political competition, competition, government, US, economic development

History and Industry Location: Evidence from German Airports

A central prediction of a large class of theoretical models is that industry location is not necessarily uniquely determined by fundamentals. In these models, historical accident or expectations determine which of several steady-state locations is selected. Despite the theoretical prominence of these ideas, there is surprisingly little systematic evidence on their empirical relevance. This paper exploits the combination of the division of Germany after the Second World War and the reunification of East and West Germany as an exogenous shock to industry location. We focus on a particular economic activity and establish that division caused a shift of Germany's air hub from Berlin to Frankfurt and there is no evidence of a return of the air hub to Berlin after reunification. We develop a body of evidence that the relocation of the air hub is not driven by a change in economic fundamentals but is instead a shift between multiple steady-states.Industry Location, Economic Geography, German Division, German Reunification

A particle system with cooperative branching and coalescence

In this paper, we introduce a one-dimensional model of particles performing independent random walks, where only pairs of particles can produce offspring ("cooperative branching"), and particles that land on an occupied site merge with the particle present on that site ("coalescence"). We show that the system undergoes a phase transition as the branching rate is increased. For small branching rates, the upper invariant law is trivial, and the process started with finitely many particles a.s. ends up with a single particle. Both statements are not true for high branching rates. An interesting feature of the process is that the spectral gap is zero even for low branching rates. Indeed, if the branching rate is small enough, then we show that for the process started in the fully occupied state, the particle density decays as one over the square root of time, and the same is true for the decay of the probability that the process still has more than one particle at a later time if it started with two particles.Comment: Published at http://dx.doi.org/10.1214/14-AAP1032 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org