Hans Hamburger
Encyclopedia
Hans Ludwig Hamburger was a German
mathematician
. He was a professor at universities in Berlin
, Cologne
and Ankara
.
He obtained his Ph.D. from the University of Munich in 1914 under the supervision of Alfred Pringsheim
and after war service obtained his Habilitation
for a thesis on Extensions of the Stieltjes moment problem. He was appointed Privatdozent
at the University of Berlin in 1921 and professor at the University of Cologne
in 1926. He left Germany in 1939 to avoid persecution and from 1941 to 1946 he was lecturer at the University of Southampton
, then moved to the University of Ankara in 1947, returning to Cologne in 1953.
The Hamburger moment problem is named after him. He is also noted for his work on the Carathéodory conjecture
, beginning in Berlin in 1922. His work on this topic was published only 20 years later, a reflection of the difficulty of the problem. He attributed the conjecture to Carathéodory
and his approach was a reformulation of the conjecture in terms of a bound on the index of an isolated umbilic point of a surface. Both his attribution and approach remain in place today. He proved a converse theorem
for the Riemann zeta function.
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
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 was a professor at universities in Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
, Cologne
Cologne
Cologne is Germany's fourth-largest city , and is the largest city both in the Germany Federal State of North Rhine-Westphalia and within the Rhine-Ruhr Metropolitan Area, one of the major European metropolitan areas with more than ten million inhabitants.Cologne is located on both sides of the...
and Ankara
Ankara
Ankara is the capital of Turkey and the country's second largest city after Istanbul. The city has a mean elevation of , and as of 2010 the metropolitan area in the entire Ankara Province had a population of 4.4 million....
.
He obtained his Ph.D. from the University of Munich in 1914 under the supervision of Alfred Pringsheim
Alfred Pringsheim
Alfred Israel Pringsheim was a German mathematician and patron of the arts. He was born in Ohlau, Prussian Silesia and died in Zürich, Switzerland.- Family and academic career :...
and after war service obtained his Habilitation
Habilitation
Habilitation is the highest academic qualification a scholar can achieve by his or her own pursuit in several European and Asian countries. Earned after obtaining a research doctorate, such as a PhD, habilitation requires the candidate to write a professorial thesis based on independent...
for a thesis on Extensions of the Stieltjes moment problem. He was appointed Privatdozent
Privatdozent
Privatdozent or Private lecturer is a title conferred in some European university systems, especially in German-speaking countries, for someone who pursues an academic career and holds all formal qualifications to become a tenured university professor...
at the University of Berlin in 1921 and professor at the University of Cologne
University of Cologne
The University of Cologne is one of the oldest universities in Europe and, with over 44,000 students, one of the largest universities in Germany. The university is part of the Deutsche Forschungsgemeinschaft, an association of Germany's leading research universities...
in 1926. He left Germany in 1939 to avoid persecution and from 1941 to 1946 he was lecturer at the University of Southampton
University of Southampton
The University of Southampton is a British public university located in the city of Southampton, England, a member of the Russell Group. The origins of the university can be dated back to the founding of the Hartley Institution in 1862 by Henry Robertson Hartley. In 1902, the Institution developed...
, then moved to the University of Ankara in 1947, returning to Cologne in 1953.
The Hamburger moment problem is named after him. He is also noted for his work on the Carathéodory conjecture
Carathéodory conjecture
The Carathéodory conjecture is a mathematical conjecture attributed to Constantin Carathéodory by Hans Ludwig Hamburger in a session of the Berlin Mathematical Society in 1924, [1]. Other early references are the Invited Lecture [3] of Stefan Cohn-Vossen at the International Congress of...
, beginning in Berlin in 1922. His work on this topic was published only 20 years later, a reflection of the difficulty of the problem. He attributed the conjecture to Carathéodory
Constantin Carathéodory
Constantin Carathéodory was a Greek mathematician. He made significant contributions to the theory of functions of a real variable, the calculus of variations, and measure theory...
and his approach was a reformulation of the conjecture in terms of a bound on the index of an isolated umbilic point of a surface. Both his attribution and approach remain in place today. He proved a converse theorem
Converse theorem
In the mathematical theory of automorphic forms, a converse theorem gives sufficient conditions for a Dirichlet series to be the Mellin transform of a modular form...
for the Riemann zeta function.