Karl Walter Schröter (7 September 1905 in Biebrich near

Wiesbaden Wiesbaden () is a city in central western Germany and the capital of the state of Hesse. , it had 290,955 inhabitants, plus approximately 21,000 United States citizens (mostly associated with the United States Army). The Wiesbaden urban area ...

– 22 August 1977 in

Berlin Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within ci ...

) was a German

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, structure, space, models, and change. History On ...

and

logician Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises ...

. Later on, after the war, he made important contributions concerning semantic consequences (german: semantische Folgerungsrelationen) and

provability logic Provability logic is a modal logic, in which the box (or "necessity") operator is interpreted as 'it is provable that'. The point is to capture the notion of a proof predicate of a reasonably rich formal theory, such as Peano arithmetic. Examples ...

(german: syntaktische Ableitbarkeitsrelationen). He worked as a mathematical theoretician and

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 sec ...

for the civilian

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

, the cipher bureau of the Foreign Office (german: Auswärtiges Amt), from Spring 1941 to the end of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

Personal life

From 1928 to 1936, Schröter studied mathematics,

physics Physics is the natural science that studies matter, its 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 which r ...

, philosophy, and

psychology Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries between ...

at the Universities of

Göttingen Göttingen (, , ; nds, Chöttingen) is a university city in Lower Saxony, central Germany, the capital of the eponymous district. The River Leine runs through it. At the end of 2019, the population was 118,911. General information The ori ...

Heidelberg Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914 ...

and

Frankfurt am Main Frankfurt, officially Frankfurt am Main (; Hessian: , "Frank ford on the Main"), is the most populous city in the German state of Hesse. Its 791,000 inhabitants as of 2022 make it the fifth-most populous city in Germany. Located on its na ...

. Due to family reasons he had to interrupt his studies several times. He then worked in the

mathematical logic Mathematical logic is the study of formal logic within mathematics. Major subareas include model theory, proof theory, set theory, and recursion theory. Research in mathematical logic commonly addresses the mathematical properties of formal ...

group at the

University of Münster The University of Münster (german: Westfälische Wilhelms-Universität Münster, WWU) is a public research university located in the city of Münster, North Rhine-Westphalia in Germany. With more than 43,000 students and over 120 fields of stud ...

lead by

Heinrich Scholz Heinrich Scholz (; 17 December 1884 – 30 December 1956) was a German logician, philosopher, and Protestant theologian. He was a peer of Alan Turing who mentioned Scholz when writing with regard to the reception of " On Computable Numbers, w ...

. From 1 April 1939 he was a

research assistant A research assistant (RA) is a researcher employed, often on a temporary contract, by a university, a research institute or a privately held organization, for the purpose of assisting in academic or private research. Research assistants are not in ...

at the Department of Philosophy at the

. On 20 December 1941 he took his examination for promotion of Dr. phil under the logician Heinrich Scholz studying mathematics, logic, and

calculus Calculus, originally called infinitesimal calculus or "the calculus of infinitesimals", is the mathematical study of continuous change, in the same way that geometry is the study of shape, and algebra is the study of generalizations of arithm ...

with a thesis titled ''Ein allgemeiner Kalkülbegriff'' ( en, A General Concept of Calculus). On 1 April 1941 he took a leave of absence to join

, the Foreign Office civilian cipher bureau, working as a mathematician. However, even during this time he continued to work on problems of basic mathematical research. On 19 March 1943 he presented the application to the Faculty of Philosophy and Natural Sciences, with the publication ''Axiomatisierung der Fregeschen Aussagenkalküle'' ( en, Axiomatisation of Frege's

Propositional Calculus Propositional calculus is a branch of logic. It is also called propositional logic, statement logic, sentential calculus, sentential logic, or sometimes zeroth-order logic. It deals with propositions (which can be true or false) and relations ...

), to be admitted to his Habilitation. On the basis of the positive opinions of

and

Adolf Kratzer Adolf (also spelt Adolph or Adolphe, Adolfo and when Latinised Adolphus) is a given name used in German-speaking countries, Scandinavia, the Netherlands and Flanders, France, Italy, Spain, Portugal, Latin America and to a lesser extent in var ...

, the degree of Doctor ''rerum naturalium habilitatus'' was awarded to him by certificate of 22 May 1943. On 9 June 1943 the report on the completed Habilitation was given to the Reich Minister. On 1, 2 and 3 July 1943 he held a public trial lecture on the topic ''Der Nutzen der mathematischen Logik für die Mathematik'' ( en, The Benefits of Mathematical Logic for Mathematics) as a prerequisite for a civil service position as a lecturer. On 18 August 1943 he was appointed lecturer with the authorisation to teach "Mathematical Logic and Fundamental Research", all the while still being employed in Berlin as a "scientific assistant worker" at Pers Z S. Karl Schröter remained at the University of Münster from 31 December 1943 until his contract was up on 31 April 1945, when he was taken prisoner by the

Counterintelligence Corps The Counter Intelligence Corps (Army CIC) was a World War II and early Cold War intelligence agency within the United States Army consisting of highly trained special agents. Its role was taken over by the U.S. Army Intelligence Corps in 1961 and ...

(CIC). From early May to 30 September 1945 he appeared before a joint Anglo-American Commission, first in

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

, then in

Marburg Marburg ( or ) is a university town in the German federal state (''Bundesland'') of Hesse, capital of the Marburg-Biedenkopf district (''Landkreis''). The town area spreads along the valley of the river Lahn and has a population of approxima ...

, concerning his work at Pers Z S during the war. After completion, he was dismissed in Marburg after the CIC had determined his political attitude. In the winter semester of 1945/46 he was affiliated as a lecturer in Münster. From May 1946 until his appointment to Berlin, Schröter was working at Münster as a substitute for the Review Committee of the Denazification Main Committee at the Westfälische Landesuniversität. In 1948, Karl Schröter was appointed Professor Extraordinarius for mathematical logic at Humboldt University in Berlin. In 1967, he became director of the Institute for pure mathematics of the

German Academy of Sciences at Berlin The German Academy of Sciences at Berlin, german: Deutsche Akademie der Wissenschaften zu Berlin (DAW), in 1972 renamed the Academy of Sciences of the GDR (''Akademie der Wissenschaften der DDR (AdW)''), was the most eminent research institution ...

. He was elected corresponding member in 1962 and two years later ordinary member of the German Academy of Sciences at Berlin. In 1955, Schröter together with

Günter Asser Günter Asser (26 February 1926, Berlin – 23 March 2015) was a professor emeritus of logic and mathematics at the University of Greifswald. He published numerous volumes on philosophers and mathematicians. His own research was in computabilit ...

founded the ''Zeitschrift für Mathematische Logik und Grundlagen der Mathematik'' ( en, Journal of mathematical logic and foundations of mathematics) which since 1991 is known as ''Mathematical Logic Quarterly''.

Publications

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External links

Mathematical Logic Quarterly

References

{{DEFAULTSORT:Schröter, Karl 1905 births 1977 deaths German logicians Mathematical logicians 20th-century German mathematicians German cryptographers Members of the German Academy of Sciences at Berlin