Andrzej Grzegorczyk
Encyclopedia
Andrzej Grzegorczyk ' is a Polish
mathematician
. He is known for his work in computability, logic
, and the foundations of mathematics
(Krajewski and Woleński, 2008). Grzegorczyk was the first to describe the Grzegorczyk hierarchy
, a subrecursive hierarchy that foreshadowed computational complexity theory
.
Poles
thumb|right|180px|The state flag of [[Poland]] as used by Polish government and diplomatic authoritiesThe Polish people, or Poles , are a nation indigenous to Poland. They are united by the Polish language, which belongs to the historical Lechitic subgroup of West Slavic languages of Central Europe...
mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
. He is known for his work in computability, logic
Logic
In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...
, and the foundations of mathematics
Foundations of mathematics
Foundations of mathematics is a term sometimes used for certain fields of mathematics, such as mathematical logic, axiomatic set theory, proof theory, model theory, type theory and recursion theory...
(Krajewski and Woleński, 2008). Grzegorczyk was the first to describe the Grzegorczyk hierarchy
Grzegorczyk hierarchy
The Grzegorczyk hierarchy , named after the Polish logician Andrzej Grzegorczyk, is a hierarchy of functions used in computability theory . Every function in the Grzegorczyk hierarchy is a primitive recursive function, and every primitive recursive function appears in the hierarchy at some level...
, a subrecursive hierarchy that foreshadowed computational complexity theory
Computational complexity theory
Computational complexity theory is a branch of the theory of computation in theoretical computer science and mathematics that focuses on classifying computational problems according to their inherent difficulty, and relating those classes to each other...
.