 He approached this problem in terms of the theory of k-valued discrete functions.Among the problems that were addressed in his PhD thesis titled "Issues of functional completeness in k-valued calculus" (1953) is the definitive answer to the question of completeness in 3-valued logic.Starting from 1953, Yablonsky worked at the Department of Applied Mathematics of Steklov Institute of Mathematics, that in 1966 became the separate Institute of Applied Mathematics.