Christian Stump

Preface

The 86th meeting of the Séminaire Lotharingien de Combinatoire took place from September 5 to September 8, 2021 at the beautiful Evangelische Akademie in Bad Boll (Germany) at the foot of the Schwäbischen Alb. While it was our second time in Bad Boll after 2019, it was very remarkable to meet again at an in-person meeting after such a long time of cancelled workshops over the past 18 months (with the exception of the SLC 85 one year ago). Even if the scientific talks were at the centre of attention, we will also remember this meeting for its particular circumstances. Not only did the Corona pandemic make it complicated to travel and to meet in person, but we also got the last minute information that the Deutsche Bahn went on strike for the day of arrival. Luckily and also surprisingly, this did not prevent a single participant from arriving, even if many train connections towards the area were cancelled. Given this, we were proud to be 26 participants.

The two main lecture series used our new chalk boards which we brought from Bochum:

Guillaume CHAPUY gave three lectures on "Maps, Schur Functions, and Two Views on the Tutte Equation", describing how counting maps on surfaces is intertwined with the representation theory of the symmetric groups and including beautiful drawings of maps on tori.

Martina JUHNKE-KUBITZKE delivered her lecture series on "Combinatorics of Symmetric Edge Polytopes", starting with a detailed introduction to such polytopes.

The topics of the contributed talks are detailed in the list below and included several young participants who gave their first in-person presentations of their interesting work.

We very much enjoyed the atmosphere, the hilly surrounding and the sunny weather. The evening gatherings were equally pleasant, even if it cooled down quite a bit when approaching midnight.