Gösta Mittag-Leffler

Magnus Gösta Mittag-Leffler, called Gösta, ( born March 16, 1846 in Stockholm, † July 7, 1927 in Djursholm ) was a Swedish mathematician who mainly dealt with Analysis.

Life and work

Magnus Gösta Mittag-Leffler was originally only Leffler, but opted out of reverence for his mother's family (his grandfather was a priest in the country ) with 20 years of this double name. Both parents were originally from ethnic German families who immigrated to Sweden. His father was headmaster. Mittag-Leffler was treading initially trained in insurance, but then studied from 1865 in Uppsala mathematics, which he financed through private lessons. In 1872 he received his doctorate and was at his university lecturer, but had to stay abroad for this post three years. He first went in 1873 to Paris, where he heard especially with Charles Hermite. In 1875 he went to Berlin, where he became a student of Karl Weierstrass. In 1876 he took - although Weierstrass wanted to keep him by a lecturer in Berlin - a position as a professor at the University of Helsinki as a successor of Lorenz Lindelöf ( the father of the famous mathematician Ernst Lindelöf ) to. In 1881 he became the first professor of mathematics at the University of Stockholm and a year later he married Signe Lindfors, who came from a wealthy Swedish family in Helsinki.

Mittag-Leffler founded in 1882 the mathematical journal Acta Mathematica, which co-editor of Sofya Kovalevskaya from 1884. The contributions lunch Leffler helped with the development of the Scandinavian school of mathematics that deals primarily with analysis and probability theory. Mittag-Leffler was primarily analyst who has been dealing with function theory. His best known set is the set of Mittag-Leffler that he published in the Acta Mathematica in 1884. During product Weierstrass entire functions characterized as a product over the zeros, the set of Mittag-Leffler is a series representation of meromorphic functions with poles that can be viewed as a generalization of the partial fraction decomposition of rational functions to functions with infinitely many poles. A correlation between the sets but given the fact that the logarithmic derivative of a Weierstrass product provides a Mittag-Leffler representation. First, at lunch Leffler's theorem the existence of a meromorphic function with poles in a discrete ( and infinite) is assured amount of points in the complex plane and given main parts in these poles. Any meromorphic functions with these main parts of it then differs only by an entire function. Used to prove his theorem Mittag-Leffler just created, then a controversial set theory by Georg Cantor, whose earliest supporters he belonged. This meant that the famous Berlin mathematician Leopold Kronecker, who rejected Cantor's theory passionate, not published in the Acta Mathematica. 1900-1905 studied Mittag-Leffler in a series of papers the continuation of power series outside its radius of convergence, ie, the summation of divergent series. Named after him are designated with Mittag-Leffler functions.

Mittag-Leffler became famous primarily for its role in the international mathematical community. Through his studies in Paris and Berlin shortly after the Franco-German War of 1870 he had the national Engstirnigkeiten on both sides met (although less leading mathematicians such as Charles Hermite and Karl Weierstrass was concerned ). In the Acta Mathematica, founded by him in 1882, he created a publication medium, in which communication across national borders was possible. Published at the beginning in Georg Cantor and Henri Poincaré, who published many of his most important works there. It was funded initially partly with the help of his wife's assets. He also showed how Hardy in his obituary ( Quarterly Journal London Mathematical Society, 1928 ) noted over 45 years as editor of an unerring sense of the quality of submitted work. Mittag-Leffler was finally not only in Sweden but also internationally a leading figure in mathematics. In 1916, he bequeathed his villa in the Stockholm suburb of Djursholm ( with one of the then best mathematical libraries) of the Swedish Academy of Sciences. This was today's Mittag-Leffler Institute, a central Scandinavian Research Centre for Mathematics ( which is out of Sweden financially supported by Denmark and Norway). After his death, she was led by Torsten Carleman.

In 1908 he gave a plenary lecture at the International Congress of Mathematicians in Rome ( Sur la représentation arithmétique des fonctions d'une variable complexe analytiques générales ), and also in 1900 in Paris ( Une vie de la page de Weierstrass ).

Lunch Leffler influence it is also due to that the Weierstrass Sofya Kovalevskaya student who came to his invitation in 1884 to Sweden, there was a professorship. Their inclusion in the Academy, he could not prevail.

Mittag-Leffler was an honorary member of many scientific academies of his time, he was in 1896 Foreign Fellow of the Royal Society.

He left a large estate of some 20,000 letters with pen pals 3000 ( Mittag-Leffler also preserved copies abgesendeter letters ), which is mostly in the Royal Library in Stockholm.

Others

Earlier it was sometimes claimed, Alfred Nobel would therefore have donated no Nobel Prize for mathematics, because he was afraid of personal animosity, Mittag-Leffler would get as a leading Swedish mathematician forced a price. The truth is much more prosaic, such as Lars Hörmander Lars Garding and darlegten: Nobel never came up with the idea of mathematics to give a price because that lay outside his interests. As some compensation acts the Fields Medal and the Abel Prize recently.

After Stubhaug Mittag-Leffler was also much involved in it that Marie Curie won the Nobel Prize after the committee only tended only Pierre Curie and Henri Becquerel honor ( he drew a detailed inquiries with Pierre Curie and submitted them to the Nobel Committee ) .. He also got involved in that Henri Poincaré was awarded the Nobel Prize, which he was not successful, and also for Albert Einstein.

Family

The writer Anne Charlotte Leffler 's his sister.