Supersymmetric Yang-Mills Theory as Higher Chern-Simons Theory

We observe that the string field theory actions for the topological sigma models describe higher or categorified Chern-Simons theories. These theories yield dynamical equations for connective structures on higher principal bundles. As a special case, we consider holomorphic higher Chern-Simons theory on the ambitwistor space of four-dimensional space-time. In particular, we propose a higher ambitwistor space action functional for maximally supersymmetric Yang-Mills theory.Comment: v2: 25 pages, conventions improved, typos fixed, published versio

Determinants of Further Training: Evidence for Germany

Based on a German representative sample of employees we explore the relevance and development of further training in private sector firms. We focus on formal training and explore possible individual and job-based determinants of its incidence. We also show changes over time during a 20 year observation period from 1989 to 2008. Most hypotheses are supported by the empirical evidence. Job status and firm size are the most relevant characteristics for training participation. Furthermore, our analyses reveal a general trend of rising training rates from 1989 to 2008 indicating an increased importance in the German labor market.further training, GSOEP, human capital, panel data

Credit Reporting, Relationship Banking, and Loan Repayment

This paper examines the impact of credit reporting on the repayment behavior of borrowers. We implement an experimental credit market in which loan repayment is not third-party enforceable. We then compare market outcome with a public credit registry to that without a credit registry. This experiment is conducted for two market environments: first, a market in which repeat interaction between borrowers and lenders is not feasible and, second, a market in which borrowers and lenders can choose to trade repeatedly with each other. In the market without repeat interaction the credit market collapses without a credit registry, as lenders rightly fear that borrowers will default. The introduction of a registry in this environment significantly raises repayment rates and the credit volume extended by lenders. When repeat transactions are possible a credit registry is not necessary to sustain high market performance as relationship banking enforces repayment even when lenders cannot share information. In this environment credit reporting has little impact on market efficiency, it does however affect trading structure and distribution. The presence of a credit registry leads to fewer banking relationships and reduces the ability of lenders to extract rents from such relationships.Credit Market, Information Sharing, Relationship Banking

Dynamic programming for optimal stopping via pseudo-regression

We introduce new variants of classical regression-based algorithms for optimal stopping problems based on computation of regression coefficients by Monte Carlo approximation of the corresponding $L^2$ inner products instead of the least-squares error functional. Coupled with new proposals for simulation of the underlying samples, we call the approach "pseudo regression". A detailed convergence analysis is provided and it is shown that the approach asymptotically leads to less computational cost for a pre-specified error tolerance, hence to lower complexity. The method is justified by numerical examples

Regulatory Governance Costs in Network Industries: Implicatins for postal Regulation

The various actors in regulated industries relate to each other within a broader institutional framework, i.e. by way of formal and informal rules. An important role in the implementation of liberalization processes is given to the regulation and thus to regulatory institutions. Regulation should have positive effect on social welfare. But state intervention also causes costs which we call costs of regulatory governance. These costs result from negative consequences caused by unnecessary regulatory requirements or from the implementation of inappropriate regulatory instruments. According to new institutional economics, these costs will depend upon the formal and informal rules among the involved actors, upon the allocation of property rights among these actors, as well as upon the various principal-agent or more generally contractual relationships among these actors. In this article we define an analytical framework of costs of regulatory governance. We distinguish between direct and indirect costs of regulation: Direct costs occur in relation with the institutional design of the regulatory framework and the behavior of actors. Whereas the indirect costs arise because of false incentives and finally turn out in an inefficient supply of goods and services. Using the example of the Swiss postal market we give an outline of a possible application of the framework.Regulation; Postal Sector; Regulatory Governance Costs; New Institutional Economics