Instantons and Holomorphic Couplings in Intersecting D-brane Models

We clarify certain aspects and discuss extensions of the recently introduced string D-instanton calculus (hep-th/0609191). The one-loop determinants are related to one-loop open string threshold corrections in intersecting D6-brane models. Utilising a non-renormalisation theorem for the holomorphic Wilsonian gauge kinetic functions, we derive a number of constraints for the moduli dependence of the matter field Kaehler potentials of intersecting D6-brane models on the torus. Moreover, we compute string one-loop corrections to the Fayet-Iliopoulos terms on the D6-branes finding that they are proportional to the gauge threshold corrections. Employing these results, we discuss the issue of holomorphy for E2-instanton corrections to the superpotential. Eventually, we discuss E2-instanton corrections to the gauge kinetic functions and the FI-terms.Comment: 28 pages, 5 figure

Strategic business models: opportunities for business model innovation in the automotive industry - evaluation of car subscription models and development of recommendations

Digitization and changing customer preferences have an impact on the determinants of sales and ownership in the automotive industry. In this context it is crucial to understand the new, disruptive business models and their potential for market players. The purpose of this report is to evaluate different business models that exist in the automotive industry in Germany and develop recommendations for improving key components of the recently emerged business model of car subscriptions, wherein a customer gains access to a car in return for a flat rate in the medium-term without the transfer of legal ownershi

One-loop and D-instanton corrections to the effective action of open string models

One-loop corrections to the gauge coupling and the gauge kinetic function in certain classes of four-dimensional D-brane models are computed. It is described how to determine D-instanton corrections to the superpotential and the gauge kinetic function in such models. The Affleck-Dine-Seiberg superpotential is rederived in string theory. The existence of a new class of multi-instantons, dubbed poly-instantons, is conjectured.Comment: This article is essentially the main part of the author's PhD thesi

Corporate Governance in Sweden - A Success Story?

This paper takes a performance-based approach to corporate governance and investigates whether compliance with the corporate governance code in Sweden equates to a lower cost of capital, measured as cost of equity, cost of debt and the weighted average of these, the WACC. The premonition is that adherence to governance codes should lower the risk profile of the firm, leading investors and creditors to requiring a lower premium to associate themselves with the firm financially. Previous studies, e.g. Bozec & Bozec, (2010), Pham et al, (2012) and Zhu, (2009) have established a significant relationship between the variables, although one has to be aware of the strong possibility of the presence of endogeneity. To overcome this problem, this study utilizes instrumental variables, as well as running the tests in a two-stage least-square framework with fixed-effects. A further distinction is also made by testing if SMEs have a larger relative gain of governance than large-cap listed peers. The findings are that there are financial advantages to compliance with governance. Specifically, board composition and nomination committee shows to have a significant lowering effect on the cost of capital for the whole population, being all listed companies in Sweden for the years 2008-2013. Furthermore, the relative gain is somewhat higher for SMEs compared to larger companies