On the first Dirichlet Laplacian eigenvalue of regular Polygons

The Faber-Krahn inequality in $\mathbb{R}^2$ states that among all open bounded sets of given area the disk minimizes the first Dirichlet Laplacian eigenvalue. There are numerical evidences that for all $N\ge 3$ the first Dirichlet Laplacian eigenvalue of the regular $N$-gon is greater than the one of the regular $(N+1)$-gon of same area. This natural property is also suggested by the fact that the shape of regular polygons becomes more and more "rounded" as $N$ increases and, among sets of given area, disk minimize the eigenvalue. Aiming to settle such a conjecture, in this work we investigate possible ways to estimate the difference between eigenvalues of regular $N$-gons and $(N+1)$-gons.Comment: This paper has been written for possible publication in a special volume dedicated to the conference "Third Italian-Japanese Workshop on Geometric Properties for Parabolic and Elliptic PDE's", organized in Tokyo in August 201

Die Another Day: Duration in German Import Trade

International trade patterns at the product level are surprisingly dynamic. The majority of trade relationships exist for just a few, often only two to four, years. In this paper, I examine empirically the duration in German import trade at the 8-digit product level from 1995 to 2005. I find that survival probabilities are affected by product type, exporter characteristics and market structure. Specifically, I show that the duration of exporting a product to Germany is longer for differentiated products, for products with a low elasticity of substitution, for products obtained from a large exporter that is geographically close to the German market, and for products in markets with increasing import demand.Survival, product, relationship, pattern

Trade Mispricing and Illicit Flows

A potential vehicle to move capital unrecorded out of a country is the misinvoicing of international trade transactions. Exporters may understate the export revenue on their invoices and importers may overstate import expenditures, while their trading partners are instructed to deposit the balance for their benefit in a foreign account. Aiming to quantify the extent of trade mispricing, studies have analyzed asymmetries in matched partner trade statistics or examined price anomalies in transaction level price data. This paper critically reviews these empirical approaches and briefly describes an alternative methodology. Overall, the accuracy and reliability of estimates of illicit financial flows based on trade mispricing are questioned. In particular, it is argued that estimates of trade mispricing are critically dependent on assumptions on how to interpret observed asymmetries in trade statistics. For instance, various reasons for discrepancies in bilateral trade statistics are discussed, and incentives for faking trade invoices other than capital flight are highlighted. Also, aggregate trade data may mask considerable variation in trade discrepancies at the transaction level. Most notably, the importance of trade mispricing as a method for the unrecorded cross-border transfer of capital is generally unclear.

Die another day: duration in German import trade

International trade patterns at the product level are surprisingly dynamic. The majority of trade relationships exist for just a few, often only one to three, years. In this paper, I examine empirically the duration in German import trade at the 8-digit product level from 1995 to 2005. I find that survival probabilities are affected by exporter characteristics, product type and market structure. Specifically, I show that the duration of exporting a product to Germany is longer for products obtained from countries that are economically large and geographically close to Germany; for products with large trade value and a low elasticity of substitution; and for trade pairs that command a large share of the German import market and are characterized by two-way trade. --Survival,product,relationship,pattern

Fly or Cry: Is Airport Noise Costly?

Airport noise is costly. Airport location is typically associated with lower property prices. Airport expansion often sparks protests by local residents. In this paper, I provide new evidence on the costs of airport-related noise (and other disamenities of airports) for individuals. In contrast to previous work, I analyze voting results on restricting airport operations. Using data from a referendum on the closure of one of Berlin’s inner-city airports, Tempelhof, I find that voting behavior is not primarily explained by exposure to airport disamenities. Rather, strong opposition to closure in the vicinity of Tempelhof indicates that adaptive preferences may be important.noise, preferences, traffic, airports

State Visits and International Trade

Politicians travel extensively abroad, for various reasons. One purpose of external visits is to improve bilateral economic relations. In this paper, I examine the effect of state visits on international trade. I use a large data set covering the travel activities of the heads of state of France, Germany and the United States between 1948 and 2003. My results indicate that state and official visits are indeed positively correlated with exports. A typical visit is associated with higher bilateral exports by about 8 to 10 percent, holding other things constant.head, president, government, politics, gravity

State visits and international trade

Politicians travel extensively abroad, for various reasons. One purpose of external visits is to improve bilateral economic relations. In this paper, I examine the effect of state visits on international trade. I use a large data set covering the travel activities of the heads of state of France, Germany and the United States between 1948 and 2003. My results indicate that state and official visits are indeed positively correlated with exports. A typical visit is associated with higher bilateral exports by about 8 to 10 per cent, holding other things constant. --head,president,government,politics,gravity

The classical overdetermined Serrin problem

In this survey we consider the classical overdetermined problem which was studied by Serrin in 1971. The original proof relies on Alexandrov's moving plane method, maximum principles, and a refinement of Hopf's boundary point Lemma. Since then other approaches to the same problem have been devised. Among them we consider the one due to Weinberger which strikes for the elementary arguments used and became very popular. Then we discuss also a duality approach involving harmonic functions, a shape derivative approach and a purely integral approach, all of them not relying on maximum principle. For each one we consider pros and cons as well as some generalizations

Gotcha! A Profile of Smuggling in International Trade

This paper explores official trade data to identify patterns of smuggling in international trade. Our main measure of interest is the difference in matched partner trade statistics, i.e., the extent to which the recorded export value in the source country deviates from the reportedimport value in the destination country. Analyzing 4-digit product level data for the world’s five largest importers for the period from 2002-2006, we find that the reporting gaps are highly correlated with the level of corruption in both partner countries. This finding supports the hypothesis that trade gaps partly represent smuggling activities.corruption, illicit, illegal, trade, statistics, tariffs