Andrzej Grzegorczyk

Andrzej Grzegorczyk [ˈandʐɛj ɡʐɛˈɡɔrt͡ʂɨk] (22 August 1922 – 20 March 2014) was a Polish mathematician and philosopher. He is known for his work in computability, logic, and the foundations of mathematics (Krajewski and Woleński, 2008).

Grzegorczyk was born in Warsaw, Commonwealth of Poland. He became the first to describe the Grzegorczyk hierarchy, a subrecursive hierarchy that foreshadowed computational complexity theory. He died in Warsaw on 20 March 2014 of natural causes, at the age of 91.