In society Marathon August 9, 2021 Alexander Cherkasov This morning, at dawn, at the fifth hour of the morning, Sergey Adamovich Kovalev died in a dream. Our senior comrade, teacher, colleague. Typly argued with us, and with opponents, and with fate. A scientist, a researcher who was looking for a system in everything. Fighting with the system, sometimes defeating, but also in defeat and in despair not discouraged.