Grigori Samuilovitsch Tseitin (Russian: Григорий Самуилович Цейтин, born November 15, 1936 in Leningrad, USSR, deceased August 27, 2022 in Campbell, CA, USA) was a Russian mathematician and computer scientist, who moved to the United States in 1999.
He earned his PhD in 1960 under the supervision of Andrei Andreevich Markov.
His dissertation was called "Algorithmic Operators on Constructive Complete Separable Metric Spaces".
[2] In 1968, he received the Russian doctoral degree (corresponding to a habilitation) from the same university.
From 1960 to 2000 Tseitin worked at the Smirnov Research Institute of Mathematics and Mechanics at SPbSU [ru][3] and taught classes in computer science at his alma mater.