Albert Muchnik

Albert Abramovich Muchnik (2 January 1934 – 14 February 2019) was a Russian mathematician who worked in the field of foundations and mathematical logic.

He received his Ph.D. from Moscow State Pedagogical Institute in 1959 under the advisorship of Pyotr Novikov.

He and Richard Friedberg independently introduced the priority method which gave an affirmative answer to Post's problem regarding the existence of recursively enumerable Turing degrees between 0 and 0' .

This result, now known as the Friedberg–Muchnik theorem,[2][3] opened study of the Turing degrees of the recursively enumerable sets which turned out to possess a very complicated and non-trivial structure.

Their son Andrey Muchnik, who died in 2007, was also a mathematician working in foundations of mathematics.