Quadratic Forms and Real Algebra

Dortmund, 26-27 October 2023
Conference on the occasion of Eberhard Becker's 80th birthday



Karim Johannes Becher
Detlev Hoffmann
Daniel Plaumann


Thursday, 26 October
9:30 Welcome
10:00-10:45 R. Scharlau: Biographical Notes
- Coffee break -
11:15-12:00 M. Knebusch: Quadratic Forms on Modules over Semirings : New Ways (Abstract / Link to paper)
- Lunch -
13:15-14:00 L. Bröcker: All the Way with Pythagoras (Slides)
14:00-14:45 F. Delon: Sums of 2n-th Powers and Orderings of Higher Level
- Coffee break -
15:15-16:00 P. Felke: Post-Quantum Cryptography (Abstract / Slides)
from 18:30 Conference dinner

Friday, 27 October
9:30-10:15 J.-L. Colliot-Thélène: Rationalitätsfragen bei Familien von reellen Quadriken (Zusammenfassung)
- Coffee break -
10:45-11:30 C. Scheiderer: Sums of squares in polynomial optimization (Abstract)
11:45-12:30 K. Schmüdgen: Positivstellensätze for semirings (Abstract / Slides)
- Lunch -
13:45-14:30 F.-V. Kuhlmann: Density of various subsets in spaces of places of function fields, and applications to real holomorphy rings (Abstract / Slides)
14:45-15:30 W. Kucharz: Approximation and homotopy in real algebraic geometry (Abstract)
- Coffee break -
16:00-16:45 M.-F. Roy: Elementary recursive degree bounds for Hilbert’s 17th problem and Positivstellensatz (Abstract / Slides)

Saturday, 28 October
City tour with Eberhard, (approx. 10am-1pm, followed by lunch)

Group photo

(Most, but unfortunately not all, participants and organizers...)