Berlin-Poznań-Hamburg-Warsaw Seminar on Discrete Mathematics 2021 will be held on September 24-25 in Będlewo (near Poznań).
List of participants: http://zmd.home.amu.edu.pl/sites/default/files/BPHW21participants.pdf
Program: http://zmd.home.amu.edu.pl/sites/default/files/BPHW21program.pdf
Photos of participants: 
