Groups as Galois Groups
An Introduction

Develops the mathematical background and recent results on the Inverse Galois Problem.

Helmut Volklein (Author)

9780521065030, Cambridge University Press

Paperback / softback, published 12 June 2008

268 pages, 6 b/w illus.
22.9 x 15 x 1.5 cm, 0.396 kg

Review of the hardback: '… a very helpful introduction into an active research area, recommended for graduate students and anyone interested in recent progress in the inverse Galois problem.' B. H. Matzat, Bulletin of London Mathmatical Society

This book describes various approaches to the Inverse Galois Problem, a classical unsolved problem of mathematics posed by Hilbert at the beginning of the century. It brings together ideas from group theory, algebraic geometry and number theory, topology, and analysis. Assuming only elementary algebra and complex analysis, the author develops the necessary background from topology, Riemann surface theory and number theory. The first part of the book is quite elementary, and leads up to the basic rigidity criteria for the realisation of groups as Galois groups. The second part presents more advanced topics, such as braid group action and moduli spaces for covers of the Riemann sphere, GAR- and GAL- realizations, and patching over complete valued fields. Graduate students and mathematicians from other areas (especially group theory) will find this an excellent introduction to a fascinating field.

Part 1. The Basic Rigidity Criteria: 1. Hilbert's irreducibility theorem
2. Finite Galois extensions of C (x)
3. Descent of base field and the rigidity criterion
4. Covering spaces and the fundamental group
5. Riemann surfaces and their functional fields
6. The analytic version of Riemann's existence theorem
Part II. Further Directions: 7. The descent from C to k
8. Embedding problems: braiding action and weak rigidity
Moduli spaces for covers of the Riemann sphere
Patching over complete valued fields.

Subject Areas: Groups & group theory [PBG]