Program
Schedule
On wednesday afternoon the workshop turns into the AKLS seminar on automorphic forms.
| Monday | |||
|---|---|---|---|
| 14:00 - 14:05 | Welcome | ||
| 14:05 - 15:05 | Jacques Martinet | From positive definite quadratic forms to Euclidean lattices | Slides |
| -- Coffee break -- | |||
| 16:00 - 16:30 | Bertrand Meyer | Some constructions of maximal witness codes | Slides |
| 16:45 - 17:15 | Elisabeth Nossek | Dual strongly perfect lattices | Slides |
| 17:30 - 18:00 | Rudolf Scharlau | Extremality of modular forms, lattices and sphere packings | |
| Tuesday | |||
| 09:15 - 10:15 | Siegfried Boecherer | Harmonic polynomials for quadratic forms with hermitian structure and associated theta series | |
| -- Coffee break -- | |||
| 11:00 - 11:30 | Boris Venkov | Unimodular lattices and strongly regular graphs (some examples and problems) | |
| 11:45 - 12:15 | Annika Meyer | On a recursive decoding algorithm for glued lattices | Slides |
| -- Lunch -- | |||
| 14:00 - 15:00 | Wilhelm Plesken | Codes and hyperplane arrangements | |
| -- Coffee break -- | |||
| 16:00 - 16:30 | Richard Parker | Integral laminated lattices | Slides (odp) |
| 16:45 - 17:30 | Rainer Schulze-Pillot-Ziemen | On extremal modular forms | |
| Wednesday | |||
| 09:15 - 10:15 | Heinz-Georg Quebbemann | Type II self-dual algebraic geometric codes | |
| -- Coffee break -- | |||
| 11:00 - 11:30 | Manabu Oura | Some consequences of the work of Nebe-Rains-Sloane | |
| 11:45 - 12:15 | Gabriele Nebe | Automorphisms of extremal codes | |
| -- Lunch -- | |||
| 14:00 - 14:05 | Welcome (Seminar Aachen-Köln-Lille-Siegen) | ||
| 14:05 - 14:55 | Christine Bachoc | Lower bounds for the measurable chromatic number of Euclidean space | Slides |
| 15:00 - 15:50 | Valentin Blomer | Counting rational points on a cubic surface | |
| -- Coffee break -- | |||
| 17:00 - 17:50 | Jan Bruinier | On the converse theorem for Borcherds products | |
| -- Dinner -- | |||
| Thursday | |||
| 09:00 - 09:20 | David Lorch | Einklassige Geschlechter 3-dimensionaler Gitter | |
| 09:30 - 09:50 | Michael Jürgens | Nicht-Existenz extremaler Gitter: eine weitere Anwendung der Methode von Bachoc-Venkov | Slides |
| 10:00 - 10:20 | Juan Marcos Cerviño | Infinitesimal aspects of the theta-series map | |
| -- Coffee break -- | |||
| 11:00 - 11:20 | Stefan Höppner / Timo Rosnau | Ganzzahlige orthogonale Darstellungen der zyklischen Gruppe, Teil I | Slides |
| 11:30 - 11:50 | Björn Hoffmann | Ganzzahlige orthogonale Darstellungen der zyklischen Gruppe, Teil II | Slides |
| 12:00 - 12:20 | Jan Jongen | Lattices over twisted group rings and rational forms of finite groups | Slides |
Abstracts
Jan Jongen: Lattices over twisted group rings and rational forms of finite groups
At first I will discuss the relationship between finite matrix groups which are defined over the rational numbers and modules over certain skew group rings K wreath G. These skew group rings come with a natural Z-order Z_K wreath G. Using this order I will show that in some cases it is possible to construct (algorithmically) the full (Z_K wreath G)-lattices in a given module V. In general this works along the same lines as the group ring case.