The book addresses a key question in topological field theory and logarithmic conformal field theory: In the case where the underlying modular category is not semisimple, topological field theory appears to suggest that mapping class groups do not only act on the spaces of chiral conformal blocks, which arise from the homomorphism functors in the category, but also act on the spaces that arise from the corresponding derived functors. It is natural to ask whether this is indeed the case. The book carefully approaches this question by first providing a detailed introduction to surfaces and their mapping class groups. Thereafter, it explains how representations of these groups are constructed in topological field theory, using an approach via nets and ribbon graphs. These tools are then used to show that the mapping class groups indeed act on the so-called derived block spaces. Toward the end, the book explains the relation to Hochschild cohomology of Hopf algebras and the modular group.

Computeralgebra- Systeme wie MAPLE gehoeren heute zum Alltag aller, die Mathematik in Schule, Wirtschaft und Hochschule anwenden. Gleichzeitig bieten sie die Moeglichkeit, in ganz anderer Weise Beispiele zu untersuchen und zu veranschaulichen, als dies mit Bleistift und Papier moeglich ist. Neben einer Einfuhrung in MAPLE hat dieses Buch zum Ziel, durch die Behandlung von Beispielen den Stoff des ersten Studienjahres, wie er in den Vorlesungen zur Analysis und Linearen Algebra behandelt wird, zu vertiefen und zu veranschaulichen. Es besteht aus Aufgaben mit Erlauterungen, anhand derer der Leser den Stoff eigenstandig durcharbeiten soll. Mathematische Anwendersysteme als berufsbildende Kompetenz in der Bachelor-Ausbildung: Das Buch eignet sich fur ein Modul aufbauend auf den Grundvorlesungen Analysis und Lineare Algebra. Materialien zu diesem Buch fur das E-Learning System OKUSON werden fur Dozenten unter OnlinePLUS bereitgestellt.

This is an introduction to Lie algebras and their applications in physics. The first three chapters show how Lie algebras arise naturally from symmetries of physical systems and illustrate through examples much of their general structure. Chapters 4 to 13 give a detailed introduction to Lie algebras and their representations, covering the Cartan-Weyl basis, simple and affine Lie algebras, real forms and Lie groups, the Weyl group, automorphisms, loop algebras and highest weight representations. Chapters 14 to 22 cover specific further topics, such as Verma modules, Casimirs, tensor products and Clebsch-Gordan coefficients, invariant tensors, subalgebras and branching rules, Young tableaux, spinors, Clifford algebras and supersymmetry, representations on function spaces, and Hopf algebras and representation rings. A detailed reference list is provided, and many exercises and examples throughout the book illustrate the use of Lie algebras in real physical problems. The text is written at a level accessible to graduate students, but will also provide a comprehensive reference for researchers.