Sergei Adian

Sergei Ivanovich Adian (1931-2020) was a Soviet and Armenian mathematician born near Elizavetpol, now Ganja, Azerbaijan, who spent his career as a professor at Moscow State University. Working under his advisor Pyotr Novikov, he proved by 1955 the undecidability of nearly all non-trivial invariant group properties, a result now known as the Adian-Rabin theorem. Over eight years of collaboration with Novikov he helped solve the classical Burnside problem in 1968, showing a negative solution for all odd periods greater than 4381, one of the deepest results in twentieth-century algebra. He mentored numerous mathematicians, including Alexander Razborov.