Due to the Corona pandemic, the symposium originally planned for 2020 has been postponed to 2022. We plan to keep the same topic "The Ball" with the same speakers as much as possible. Very few had to cancel their contribution, a few others are currently still unsure whether they will be able to attend the conference in 2022. Therefore, we would now like to start a supplementary call for contributions.
Contributions are welcome in all categories. Submissions that we cannot consider, will be put on a waiting list in case further speakers will not be able to come.