A continuous, constructive solution to Hilbert's 17th problem.
A note on the pp conjecture for sheaves of spaces of orderings
In this note we provide a direct and simple proof of a result previously obtained by Astier stating that the class of spaces of orderings for which the pp conjecture holds true is closed under sheaves over Boolean spaces.
Bilinear forms for SL(2,q), An and similar groups.
The set of invariant symmetric bilinear forms on irreducible modules over fields of characteristic zero for certain groups is studied. Results are obtained under the presence in a finite group of elements of order four whose square is central. In particular, we find that the relevant modules for the groups mentioned in the title always accept an invariant symmetric bilinear form under which the module admits an orthonormal basis.
Binäre Formen und Primideale.
Class numbers of binary quadratic forms over algebraic number fields.
Constructing Quasi-Pythagorean Fields
Corrigendum to the paper "Hermitian forms over division algebras over real function fields".
Darstellungen mit Nebenbedingungen durch quadratische Formen.
Definite Lattices Over Real Algebraic Function Domains.
Dimensions of anisotropic indefinite quadratic forms. I.
Dimensions of anisotropic indefinite quadratic forms. II.
Eine Bemerkung zu den höheren Pythagoraszahlen reeller Körper.
Ergänzung zur Arbeit "Quadratische Formen über affinen Algebren und ein algebraischer Beweis des Satzes von Borsuk-Ulam".
Fibrés quadratiques et composantes connexes réelles.
Fields with non-trivial Kaplansky's radical and finite square class number
Fields with Prescribed Quadratic Form Schemes.
Formally real fields, pythagorean fields, C-fields and W-groups.
Forms Derived from the Arithmetic-Geometric Inequality.
Generalized Hilbert fields.
Generalized Hubert fields, II