Christian Wei – författare

These notes introduce a new class of algebraic curves on Hilbert modular surfaces. These curves are called twisted Teichmüller curves, because their construction is very reminiscent of Hirzebruch-Zagier cycles. These new objects are analyzed in detail and their main properties are described. In particular, the volume of twisted Teichmüller curves is calculated and their components are partially classified. The study of algebraic curves on Hilbert modular surfaces has been widely covered in the literature due to their arithmetic importance. Among these, twisted diagonals (Hirzebruch-Zagier cycles) are some of the most important examples.

STATISTICA unterstützt die statistische und grafische Analyse von Datenmaterial. Nach einer Einführung in die grundlegende Bedienung von STATISTICA werden in diesem Buch zahlreiche Verfahren der deskriptiven und explorativen Statistik vorgestellt. Im Anschluss daran erläutert der Autor eine Reihe wichtiger Testverfahren sowie Ansätze zur Datenmodellierung. Das Kapitel zur statistischen Qualitätskontrolle zeigt exemplarisch, wie Six Sigma und STATISTICA im unternehmerischen Alltag zusammenspielen. Abgerundet wird dieses Lehrbuch durch einen Kompaktkurs zu MySQL und Visual Basic, so dass das Buch ohne zusätzliche Begleitlektüre durchgearbeitet werden kann. Übungsaufgaben am Ende eines jeden Kapitels erleichtern es, den Lernfortschritt zu überprüfen.

Seminar paper from the year 2005 in the subject Business economics - Banking, Stock Exchanges, Insurance, Accounting, grade: 2,0, University of Regensburg, course: Empirical Capital Market Research, language: English, abstract: What were the reasons for the great c rash of the Long-Term Capital Management (LTCM) of hedge funds in 19981? In short: predatory trading. But what is predatory in effect? How can predatory trading occur? What are the consequences of predatory trading? How can predatory trading be avoided? These questions will be answered in the following paper. The following description gives a first impression of predatory trading: "e;When you smell blood in the water, you become a shark. ... when you know that one of your number is in trouble ... you try to figure out what he owns and you start shorting those stocks ..."e;2The first part of this paper deals with the basics of the model of the predatory trading theory, the second part elaborates the advantages and disadvantages which are summed up in the last part.

Seminar paper from the year 2006 in the subject Business economics - Investment and Finance, grade: 1,3, European Business School - International University Schlo Reichartshausen Oestrich-Winkel, course: Seminar Retail Banking, language: English, abstract: German banks have come under pressure for their disappointing profitability. Indeed, rankings of developed nations along profitability indicators place Germany at the end of the scale. Critics attribute that situation mainly to the German banking system being overbanked and overbranched. The purpose of this paper is to analyze that notion and to examine the German market and competitive landscape of the retail banking industry. The analysis contains four sections. The first section compares profitability ratios and indicators of German banks to their peers performances. The study produces surprising results. Despite the ostensibly high branch density, Germany s banks operate very cost efficiently. Yet it is their inability to generate sufficient income that results in the sluggish net earnings. Consequently, in the second section, the authors examine the German banking system and portray and compare its peculiarities in order to find out if the income problems are inherent to the system. More than in any other country, public banks dominate the market and, together with the cooperative banks, do not follow the economic principle of profit maximization. Moreover, the public banks have also received unjust government subsidies in the form of the maintenance and guarantee obligations. Thus, one presumes that private German banks operate in a very difficult system. The third section then takes a closer look at the market and analyzes the bank density, branch density and competition which the system produces. In the past, waves of intra-group consolidations have occurred. Similarly, branch networks have been thinned out especially by the private banks in an effort to cut costs. The result is that the current situation does not appear overly overbanked when put into perspective to the population, area, productivity and customer business. However, the German banking market is very competitive, and calls for further consolidations aim at decreasing competition rather than realizing synergies. In the fourth and last section, an appraisal of the current system is presented. Customers benefit from the current structure as it allows for easier access to credit compared to other countries, offers banking services to everybody at low costs and appears to be inherently stable. Thus, Germany is overbanked in the sense of high competition which negatively impacts bank profitability. Yet good companies should also be profitable in a competitive environment.

Diploma Thesis from the year 2007 in the subject Business economics - Banking, Stock Exchanges, Insurance, Accounting, grade: 2,3, University of Regensburg, language: English, abstract: There are many consultancies, for example, Interbrand, Brand Finance or Batten, Barton, Durstine & Osborn (BBDO) that create annual lists of companies ranked by their brand value. Over the years, these popular rankings have become more and more relevant to companies because they are of the opinion that they can thereby increase their degree of popularity. Therefore, an interesting question arises: Is there any connection between the company's brand value and its financial performance? The list of the one hundred most valued brands published by Interbrand, probably the most famous global branding consultancy of the world, has made its contribution to the increased popularity of brand value, not only in the United States but meanwhile also in Europe. If you peruse the best global brands 2006 list attentively, you will observe that nearly half of thecompanies, exactly 49%, are non-US companies, compared to only 37% inthe year 2001. 37 of the 100 companies are from Europe, with Nokia as the most valuable European brand ranked as number six. Moreover, nine companies are based in Germany, sorted by brand value: Mercedes, BMW, SAP, Siemens, Volkswagen, adidas, Audi, Porsche, and Nivea. Further evidence for the raised acceptance and attractiveness of intangible assets, brand value included, provides the fact that since the early 1980s the share of intangible assets of concerns has increased from an average of 40% in their brand value to over 80% by the end of the 1990s. As a result, only about 20% of a company s brand value will be recorded by the accounting system. Thus, it is difficult for the companies to explain this overvalue to theshareholders. The first part of this paper deals with intangible assets in general. The first part concludes with the description of the results of other empirical studies about the connection between brand value and stock performance. The second part of the working paper examines the relationship between brand value and stock performance of the EuroStoxx 50 companies. First, the empirical analysis is described, followed by the presentation of the results of the investigation. These results are then summarised and interpreted. The information criteria will be explained hereafter. Finally yet importantly, thestatistical tests based on the results of the study are summed up.

In diesem Lehrbuch wird der moderne Lebesguesche Integralbegriff ausführlich entwickelt und auf eine vielfältige Klasse von geometrischen Objekten, sogenannte Untermannigfaltigkeiten, übertragen. Der vorliegende zweite Band richtet den Fokus stärker auf höhere Dimensionen und stellt zusammen mit dem ersten Band eine umfassende Einführung in die Analysis dar. Die mathematischen Grundlagen werden durch zahlreiche *-Kapitel erweitert, welche die Beziehungen der erlernten Inhalte zu anderen Teilgebieten der Mathematik aufzeigen und die Bedeutung der Analysis für praktische Anwendungen verdeutlichen. Darüber hinaus enthält dieses Buch mehr als 50 Übungsaufgaben inklusive Lösungen, sodass es sich sehr gut für Prüfungsvorbereitungen und zum Selbststudium eignet.

Dieses Lehrbuch behandelt alle wesentlichen Grundlagen der Analysis mit Fokus auf den eindimensionalen Fall. Darüber hinaus werden in zahlreichen Exkursionen konkrete Bezüge der erlernten Inhalte zu Anwendungen in der Praxis sowie anderen Bereichen der Mathematik aufgezeigt. Dazu werden die gängigen Grundlagen um sogenannte *-Kapitel erweitert. Die klare Struktur und der logische Aufbau ermöglichen es dem Leser, schnell zu den wichtigen Inhalten vorzustoßen. Alle zentralen Aussagen der Analysis werden ausführlich bewiesen und die dafür notwendigen Grundlagen der linearen Algebra im Anhang zusammengefasst. Weiterhin enthält dieses Buch mehr als 80 Übungsaufgaben inklusive Lösungen, sodass es sich sehr gut zur Prüfungsvorbereitung und zum Selbststudium eignet.

Bei der Anwendung finanzmathematischer Modelle im beruflichen Alltag ist es ein entscheidender Erfolgsfaktor, die Verknüpfung von Theorie und Praxis zu verstehen. Dieses Buch verbindet daher die Präsentation der Theorie hinter den zentralen Themen der Finanzmathematik durchgehend mit vielen Beispielen aus einem konkreten Anwendungsfeld. Dabei bringen die Autoren fortwährend ihre langjährigen Erfahrungen als Berufstätige in der Finanzbranche und als Wissenschaftler ein. In besonderer Weise richtet sich dieses Buch dadurch an Studierende der Mathematik, der Betriebs- und der Volkswirtschaftslehre, die sich für einen Schwerpunkt in Finanzmärkten und Anlagestrategien interessieren. 

Ergänzt wird die klare und verständliche Darstellung durch mehr als 60 Aufgaben inklusive Lösungen, die auch als Onlineressourcen in Excel umgesetzt und verfügbar sind. Damit keine weitere Literatur zu erforderlichen Vorkenntnissen herangezogen werden muss, sind in einem Anhang die notwendigen Grundlagen aus der Wirtschaftsmathematik und Statistik in kompakter und übersichtlicher Form zusammengefasst, sodass das vorliegende Buch auch für das Selbststudium hervorragend genutzt werden kann. Dadurch ist es ebenfalls im hohen Maße für Berufstätige aus der Praxis geeignet, die einen Hintergrund in den Wirtschaftswissenschaften oder der Mathematik mitbringen und auf der Suche nach einer anschaulichen und praxisorientierten Einführung sind oder ihr Wissen auffrischen möchten.