Rudolf Paul Joachim Kochendörffer (21 November 1911 in

Pankow Pankow () is the second largest and most populous Boroughs and quarters of Berlin, borough of the German capital Berlin. In Berlin's 2001 administrative reform, it was merged with the former boroughs of Prenzlauer Berg and Weissensee (Berlin), W ...

– 23 August 1980 in

Dortmund Dortmund (; ; ) is the third-largest city in North Rhine-Westphalia, after Cologne and Düsseldorf, and the List of cities in Germany by population, ninth-largest city in Germany. With a population of 614,495 inhabitants, it is the largest city ...

) was a

German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

and professor of mathematics in the

University of Rostock The University of Rostock () is a public university located in Rostock, Mecklenburg-Vorpommern, Germany. Founded in 1419, it is the third-oldest university in Germany. It is the oldest university in continental northern Europe and the Baltic Se ...

specialising in

algebra Algebra is a branch of mathematics that deals with abstract systems, known as algebraic structures, and the manipulation of expressions within those systems. It is a generalization of arithmetic that introduces variables and algebraic ope ...

group theory In abstract algebra, group theory studies the algebraic structures known as group (mathematics), groups. The concept of a group is central to abstract algebra: other well-known algebraic structures, such as ring (mathematics), rings, field ( ...

and theory of

finite group In abstract algebra, a finite group is a group whose underlying set is finite. Finite groups often arise when considering symmetry of mathematical or physical objects, when those objects admit just a finite number of structure-preserving tra ...

s and their representation. During

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, Kochendörffer worked as a mathematical

cryptanalyst Cryptanalysis (from the Greek ''kryptós'', "hidden", and ''analýein'', "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic se ...

in the mathematical referat of Inspectorate 7/IV, that would later become part of Referat I of Group IV of the

General der Nachrichtenaufklärung () was the signals intelligence agency of the German Army (1935-1945), Heer (German Army), before and during World War II. It was the successor to the former cipher bureau known as Inspectorate 7/VI in operation between 1940 and 1942, when it wa ...

(abbr. GDNA), the

signals intelligence Signals intelligence (SIGINT) is the act and field of intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly u ...

agency of the

Wehrmacht The ''Wehrmacht'' (, ) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the German Army (1935–1945), ''Heer'' (army), the ''Kriegsmarine'' (navy) and the ''Luftwaffe'' (air force). The designation "''Wehrmac ...

and was known as a cryptographic tester of the Enigma cipher machine. Kochendörffer was a Member of the Scientific Advisory Council for Mathematics at the State Secretariat for the Higher and Specialist Schools of the GDR, a staff member of

Mathematical Reviews ''Mathematical Reviews'' is a journal published by the American Mathematical Society (AMS) that contains brief synopses, and in some cases evaluations, of many articles in mathematics, statistics, and theoretical computer science. The AMS also pu ...

and collaborated with the

Zentralblatt MATH zbMATH Open, formerly Zentralblatt MATH, is a major reviewing service providing reviews and abstracts for articles in pure and applied mathematics, produced by the Berlin office of FIZ Karlsruhe – Leibniz Institute for Information Infrastru ...

Life

Rudolf Kochendörffers father, Albert Kochendörffer(1877-1958) was a lending bookseller (). His mother was Bertha Kochendörffer.

Education

In 1930, Kochendörffer completed his

Abitur ''Abitur'' (), often shortened colloquially to ''Abi'', is a qualification granted at the end of secondary education in Germany. It is conferred on students who pass their final exams at the end of ISCED 3, usually after twelve or thirteen year ...

. Kochendörffer subsequently studied at the

Technische Hochschule A ''Technische Hochschule'' (, plural: ''Technische Hochschulen'', abbreviated ''TH'') is a type of university focusing on engineering sciences in Germany. Previously, it also existed in Austria, Switzerland, the Netherlands (), and Finland (, ) ...

in Charlottenburg (now

Technische Universität Berlin (TU Berlin; also known as Berlin Institute of Technology and Technical University of Berlin, although officially the name should not be translated) is a public university, public research university located in Berlin, Germany. It was the first ...

) from 1930 to 1936 on the study of

mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

and

philosophy Philosophy ('love of wisdom' in Ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, Value (ethics and social sciences), value, mind, and language. It is a rational an ...

Career

In 1936, he was promoted to

Dr Phil Phillip Calvin McGraw (born September 1, 1950), also known as Dr. Phil, is an American television personality and author who is best known for hosting the talk show ''Dr. Phil''. He holds a doctorate in clinical psychology, though he ceased ...

, with a doctoral thesis titled: ''Investigations on a presumption of W. Burnside'' (German:Untersuchungen über eine Vermutung von W. Burnside) (

Burnside's theorem In mathematics, Burnside's theorem in group theory states that if ''G'' is a finite group of order p^a q^b where ''p'' and ''q'' are prime numbers, and ''a'' and ''b'' are non-negative integers, then ''G'' is solvable. Hence each non-Abelian fin ...

). His doctoral advisors where

Ludwig Bieberbach Ludwig Georg Elias Moses Bieberbach (; 4 December 1886 – 1 September 1982) was a German mathematician and leading representative of National Socialist German mathematics (" Deutsche Mathematik"). Biography Born in Goddelau, near Darmstadt, ...

Issai Schur Issai Schur (10 January 1875 – 10 January 1941) was a Russian mathematician who worked in Germany for most of his life. He studied at the Humboldt University of Berlin, University of Berlin. He obtained his doctorate in 1901, became lecturer i ...

and

Erhard Schmidt Erhard Schmidt (13 January 1876 – 6 December 1959) was a Baltic German mathematician whose work significantly influenced the direction of mathematics in the twentieth century. Schmidt was born in Tartu (), in the Governorate of Livonia (now ...

. but was forced to resign as a Jew in 1935. During 1938-1939 he worked as an assistant at the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen (, commonly referred to as Georgia Augusta), is a Public university, public research university in the city of Göttingen, Lower Saxony, Germany. Founded in 1734 ...

. From 1939 to 1942 he was an assistant to the cryptanalysis department

Pers Z S The Pers Z S was the signals intelligence agency of the German Foreign Office () before and during World War II. It consisted of two cryptologic sections. Pers Z S was the cryptanalytic section which was called ''Special Service of Z Branch of th ...

of the

Foreign Office Foreign may refer to: Government * Foreign policy, how a country interacts with other countries * Ministry of Foreign Affairs, in many countries ** Foreign Office, a department of the UK government ** Foreign office and foreign minister * United ...

and from 1942-1945 he was employed as a mathematical cryptanalysis in the OKW/Chi and the GDNA. from 1946 to 1948 he worked as a Senior assistant at the Mathematical Institute of the

Humboldt University of Berlin The Humboldt University of Berlin (, abbreviated HU Berlin) is a public research university in the central borough of Mitte in Berlin, Germany. The university was established by Frederick William III on the initiative of Wilhelm von Humbol ...

. In 1948, Kochendörffer

habilitated Habilitation is the highest university degree, or the procedure by which it is achieved, in Germany, France, Italy, Poland and some other European and non-English-speaking countries. The candidate fulfills a university's set criteria of excellen ...

in the subjects of mathematics in Berlin, and was promoted to full

professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...

. He then appointed to position as professor of mathematics at the

University of Greifswald The University of Greifswald (; ), formerly known as Ernst-Moritz-Arndt University of Greifswald, is a public research university located in Greifswald, Germany, in the state of Mecklenburg-Western Pomerania. Founded in 1456, it is one of th ...

, for a year . At the start of the new decade in 1950, Kochendörffer became a professor of Mathematics at the

, a position he held until 1966.

Research

Kochendörffer specialized in

. He was also published algebra textbooks. Between 1967-1970 Kochendörffer was visiting professor of Mathematics, Faculty of Natural Sciences at the

Johannes Gutenberg University of Mainz The Johannes Gutenberg University Mainz () is a public research university in Mainz, Rhineland Palatinate, Germany. It has been named after the printer Johannes Gutenberg since 1946. it had approximately 32,000 students enrolled in around 100 a ...

, and at the

University of Tasmania The University of Tasmania (UTAS) is a public research university, primarily located in Tasmania, Australia. Founded in 1890, it is Australia's fourth oldest university. Christ College (University of Tasmania), Christ College, one of the unive ...

. Between 1970-1977, Kochendörffer finished his career as professor of Mathematics at

TU Dortmund University TU Dortmund University () is a technical university in Dortmund, North Rhine-Westphalia, Germany with over 35,000 students, and over 6,000 staff including 300 professors, offering around 80 Bachelor's and master's degree programs. It is situate ...

. He was a member of the ,

German Mathematical Society The German Mathematical Society (, DMV) is the main professional society of German mathematicians and represents German mathematics within the European Mathematical Society (EMS) and the International Mathematical Union (IMU). It was founded in ...

and the member of

Gesellschaft für Angewandte Mathematik und Mechanik Gesellschaft für Angewandte Mathematik und Mechanik ("Society of Applied Mathematics and Mechanics"), often referred to by the acronym GAMM, is a German society for the promotion of science, founded in 1922 by the physicist Ludwig Prandtl and the ...

Awards and honours

In 1960, he was awarded the

Patriotic Order of Merit The Patriotic Order of Merit (German: ''Vaterländischer Verdienstorden'', or VVO) was a national award granted annually in the German Democratic Republic (GDR). It was founded in 1954 and was awarded to individuals and institutions for outstanding ...

in Bronze, which was recognized in 1967. In 1963 he received the

National Prize of the German Democratic Republic The National Prize of the German Democratic Republic (East Germany) () was an award of the German Democratic Republic (GDR) given out in three different classes for scientific, artistic, and other meritorious achievement. With scientific achievem ...

, National Prize III. for science and technology.

Publications

* Einführung in die Algebra. Berlin 1955, 4. Aufl. 1974. (English Edition: Introduction to algebra. Groningen 1972). * Determinants and matrices (German:Determinanten und Matrizen). Leipzig 1957, 5. Aufl. 1967. (License Issue Stuttgart 1970). * Lehrbuch der Gruppentheorie. Unter besonderer Berücksichtigung der endlichen Gruppen. Leipzig 1966. (English Edition: Textbook of the group theory with special consideration of the finite groups. Leipzig 1966, English Group Theory, McGraw Hill 1970). * On supplements of finite groups. Groningen 1963.

References

{{DEFAULTSORT:Kochendorffer, Rudolf 1911 births 1980 deaths German cryptographers 20th-century German mathematicians Humboldt University of Berlin alumni Technische Universität Berlin alumni