Constantin Carathéodory
Constantin Carathéodory (Greek Κωνσταντίνος Καραθεοδωρή - Konstantínos Karatheodorí; * September 13, 1873 in Berlin, † February 2nd 1950 in Munich, in the literature is found the name as Karatheodori, Caratheodory, Carathéodori ) was a mathematician, of Greek origin.
Life
Carathéodory, was born as the son of Stephanos Carathéodory, a Greek diplomat in the service of the Ottoman Empire. The Carathéodory family has a long diplomatic tradition and diverse family members held important government posts in Constantinople Opel. A great-uncle, Alexander Carathéodory Pasha, who was also the father of his wife Euphrosyne, had represented in 1878 as Secretary of the Sublime Porte at the Congress of Berlin. The family is originally from the village Vosnochori ( Βοσνοχώρι ) today Nea Vyssa ( Νέα Βύσσα ) at Orestiada.
Carathéodory grew up in Brussels, where his father was ambassador from 1875. Already in his youth, his talent for mathematics became clear and he won several academic awards. Twice he won the first prize in mathematics at the Concours Genereaux all higher schools of the country. In 1891 he passed the Belgian high school and joined as élève étranger in the École Militaire de Belgique in Brussels. The engineering studies at this military school he graduated after four years.
As a civil engineer in the officer's rank, he went in 1895 in the Ottoman Empire to Mytilene (Lesbos ) to help out in the expansion of the road network. More developments prevented the Greek - Turkish War 1896/97. Carathéodory went to London to work a little later for a British company in the Suez Canal. In Assiout he worked for two years as Assistant Engineer for the Nile regulation. In his spare time he studied mathematics and studied the works of Jordans. He carried out measurements in the entrance of the Great Pyramid, which he published. Here he took to the great surprise of his family's determination to continue to deal exclusively with mathematics.
Carathéodory attended the Universities of Berlin (1900-1901) and Göttingen ( 1902-1904 ). For his PhD at the University of Göttingen, who enjoyed at this time because of their outstanding mathematician has an excellent international reputation, he chose the topic About the discontinuous solutions in the calculus of variations. In Göttingen, the Carathéodory talent was recognized and even the day before the viva Felix Klein went up to him with the proposal to habilitate in Göttingen. Doctoral degrees he acquired on 1 October 1904. His doctor father was Hermann Minkowski. In March of the following year he received the venia legendi, the teaching license. His habilitation thesis was submitted without notice. For three years he worked in Göttingen as a Privatdozent. In 1908 he moved to Bonn, one year later, in 1909, he became a full professor at the Technical University of Hanover. The following year he was appointed to the newly founded Institute of Technology, Wroclaw. In 1913, he returned as the successor of Felix Klein in Göttingen. In 1918 he was appointed to Berlin. Along with Albert Einstein he was admitted to the Prussian Academy of Sciences in 1919. When recording Carathéodory none other than Max Planck had spoken the eulogy.
In 1920 he received the call from the University of Smyrna, today's Izmir, appointed him President. He contributed significantly to the building at, but his work ended in 1922 with the invasion of the Turks in ruin. Carathéodory could his family in time - his wife, son and daughter - bring on the island of Samos in safety to return alone to Smyrna. There he organized the rescue precious the printed matter of the university, which he had transported on boats to Greece. Then Carathéodory found refuge with his family in Athens. Here he taught until 1924.
In 1924, he was the successor of Ferdinand Lindemann at the University of Munich. In 1925 he was elected as a full member in the mathematics and natural sciences class of the Bavarian Academy of Sciences. The request for its inclusion had signed with Alfred Pringsheim. Carathéodory 1927 was a co-signatory of the application of this class, Albert Einstein, with whom he maintained a regular correspondence with them to take as a corresponding member. At the Academy Carathéodory was among other things responsible for the publication of the works of Johannes Kepler. Him and his colleagues Oskar Perron and Heinrich Tietze was called the "Munich triumvirate of mathematics ".
1928 Carathéodory remained at some time in the United States. He held guest lectures at the University of Pennsylvania, Harvard, Princeton, and the University of Texas at Austin and the University of Texas at San Antonio.
1930 was the Greek government approach the request to him to organize the reorganization of the Universities of Athens and Thessaloniki. Carathéodory followed this request, although colleagues in Munich such as Arnold Sommerfeld tried to persuade him to stay. During this time he also wrote for the great Greek encyclopedia a post about mathematics. On the Acropolis, he examined the Parthenon. After completing this assignment, he returned to Munich. In 1938 his retirement. The period of National Socialism, he spent withdrawn as a parish of the Greek church to the Savior at Munich Salvatorplatz, where he again held a lecture on potential theory after a year's break. In the summer of 1946, he held after a serious illness his first lecture at the Mathematical Colloquium in Munich on " excess length and surface." End of January 1950, his health deteriorated again. On February 2, he died in his sufferings. Carathéodory is buried in the Munich Forest Cemetery. His wife Euphrosyne had died on 29 July 1947.
Services
Carathéodory was heavily influenced by David Hilbert. He provided fundamental results in many areas of mathematics, in particular in the theory of partial differential equations, the theory of functions ( Carathéodorysche metric ) and measure and integration theory.
His contributions to the calculus of variations, function theory, geometrical optics, thermodynamics, and to theoretical physics influenced many well-known mathematicians. From the correspondence with Albert Einstein shows that Carathéodory could give this important mathematical explanations for his foundation of the theory of relativity. The new field concept, the Carathéodory introduced in the calculus of variations, can have major consequences. Carathéodory deduced from an inequality which, 20 years later aroused among other names as Bellmansche equation or inequality in the mathematical world sensation and the basis is also radiates to the principle of dynamic optimization, and since then more than mathematics.
His studies of simple integrals in the calculus of variations were not on the level but he further developed it for the room. He also worked on variational problems of multiple integrals. Also of optics, mechanics and planetary motion, he devoted as Academician several treatises. A special place but took a thermodynamics. Even his 1909 publication published in this field ( " first axiomatically rigorous foundation of thermodynamics " ) met with acclaim by Planck and Max Born.
In the theory of functions, the set of Carathéodory is his 1913 Proven result that a conformal mapping of the unit disk has to a limited area of a Jordan curve is a continuous, bijective Continued on the edge of the unit circle. Furthermore, his 1912 result found named after him that the locally uniform convergence of a sequence of conformal mappings of the unit disk of the core convergence of image areas corresponding. In the differential geometry of him the Caratheodory conjecture is attributed to the postulated the existence of at least two umbilischer points on any smooth and closed convex surface.
In 1926, he led the general proof that no system of lenses and mirrors without optical aberrations ( aberrations) exists, with the exception of the trivial case of flat mirrors. In 1940 he published jointly with Bernhard Schmidt, a theory of mirror telescope on the theory of the Schmidt telescope, whose first specimen of this was built in Hamburg -Bergedorf and the soon further example followed at Mount Palomar. In 1932 he gave a plenary lecture at the International Congress of Mathematicians in Zurich (On the analytic mappings by functions of several variables ).
He has discovered several other mathematical theorems, including the maximum principle. The Maßerweiterungssatz of Carathéodory is still the subject of many mathematical investigations.
The Ludwig- Maximilians- University of Munich awarded in 2002 in recognition of his services to one of the largest auditoriums of the Mathematical Institute in a ceremony at the name Constantin Carathéodory auditorium. Among the guests was his daughter Despina Rodopoulou - Carathéodory.
Carathéodory enjoyed for its exceptional analytical mind and his expertise at the same time but also because of his personal integrity a high reputation far beyond his subject. In addition to his many achievements in mathematics Carathéodory is also known for his extraordinary talent for languages . His mother languages were Greek, and French. In addition, he published most of his works in German, and he spoke fluent English, Italian and Turkish.