Wittrings

InhaltsverzeichnisI: Basic facts about symmetric bilinear forms, and definition of the Wittring..§ 1 Bilinear Spaces.§ 2 Witt- and Grothendieck-rings.Appendix: Quadratic Forms.II: The structure of Wittrings.§ 1 Generators and Relations.§ 2 The prime ideals of a Wittring.§ 3 Nilpotent and torsion elements.§ 4 Application: The theorem of Artin-Pfister.§ 5 Complements to the structure theory.§ 6 Characterization of abstract Wittrings.§ 7 Fields with isomorphic Wittrings.III: Reduced Wittrings.§ 1 Von Neumann regular rings.§ 2 Topological description of reduced Wittrings.§ 3 A Nullstellensatz for Witt ideals and a generalization of the theorem of Artin-Pfister.§ 4 When are Wittrings group rings?.§ 5 Fields with strong approximation for orderings.References.