Magnus Gösta Mittag-Leffler

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Magnus 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 called Leffler, but chose this double name at the age of 20 out of admiration for his mother's family (his grandfather was a pastor in the country). Both parents came from families of German origin who immigrated to Sweden. His father was a high school director. Mittag-Leffler initially trained in insurance, but then studied mathematics at Uppsala University from 1865 , which he financed through private lessons. In 1872 he received his doctorate and became a lecturer at his university, but had to spend three years abroad for this post. He first went to Paris in 1873 , where he mainly heard from Charles Hermite . In 1875 he went to Berlin, where he became a student of Karl Weierstrass . In 1876 he accepted a position as professor at the University of Helsinki as successor to Lorenz Lindelöf (the father of the well-known mathematician Ernst Lindelöf ) - although Weierstrass wanted to hold him through a lectureship in Berlin . In 1881 he became the first mathematics professor at Stockholm University and a year later he married Signe Lindfors (1861-1921), who came from a wealthy Swedish family in Helsinki.

Bookplate for Mittag-Leffler's Acta Mathematica

Mittag-Leffler founded the mathematical journal Acta Mathematica in 1882 , of which Sofja Kowalewskaja became co-editor from 1884. Mittag-Leffler's contributions helped the further development of the Scandinavian School of Mathematics , which mainly deals with analysis and probability theory. Mittag-Leffler was primarily an analyst who dealt in particular with function theory. His most famous theorem is the Mittag-Leffler theorem , which he published in Acta Mathematica in 1884 . While Weierstrass's product theorem characterizes whole functions as a product over the zeros, Mittag-Leffler's theorem gives a series representation for meromorphic functions with poles, which can be viewed as a generalization of the partial fraction decomposition of rational functions to functions with infinitely many poles. A connection between the sentences is given by the fact that the logarithmic derivative of a Weierstrasse product provides a Mittag-Leffler representation. First, in the Mittag-Leffler theorem, the existence of a meromorphic function with poles in a discrete (also infinite) set of places in the complex number plane and given main parts in these poles is ensured. Any meromorphic function with these main parts only differs from it by a whole function. To prove his theorem, Mittag-Leffler used the then controversial set theory of Georg Cantor , one of whose earliest supporters he was. As a result, the famous Berlin mathematician Leopold Kronecker , who passionately rejected Cantor's theory, did not publish in the Acta Mathematica . From 1900 to 1905, Mittag-Leffler examined in a series of works the continuation of power series outside their radius of convergence, i.e. the summation of divergent series. The Mittag-Leffler functions marked with are named after him .

However, Mittag-Leffler was best known for his role in the international mathematical community. Through his studies in Paris and Berlin shortly after the Franco-Prussian War of 1870, he got to know the national narrow-mindedness on both sides (which, however, affected less leading mathematicians such as Charles Hermite and Karl Weierstrass ). In Acta Mathematica, which he founded in 1882, he created an organ of publication in which communication across national borders was possible. Right from the start, Georg Cantor and Henri Poincaré published in it, who published many of his most important works there. It was initially financed partly with the help of his wife's assets. In addition, as Hardy noted in his obituary ( Quarterly Journal London Mathematical Society , 1928), as editor for more than 45 years he demonstrated an unerring sense for the quality of submitted work. After all, Mittag-Leffler was a leading figure in mathematics not only in Sweden but also internationally. In 1916 he bequeathed his villa in the Stockholm suburb of Djursholm (with one of the best mathematical libraries at the time) to the Swedish Academy of Sciences. This became today's Mittag-Leffler Institute , a central Scandinavian research center for mathematics (which is financially supported not only by Sweden but also by Denmark and Norway). After his death it was headed by Torsten Carleman .

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

It is also thanks to Mittag-Leffler's influence that the Weierstrasse student Sofja Kowalewskaja , who came to Sweden at his invitation in 1884, received a professorship there. He was unable to enforce her acceptance into the academy.

Mittag-Leffler was an honorary member of many scientific academies of his time, so he became a Foreign Fellow of the Royal Society in 1896. In 1897 he was elected a member of the Leopoldina .

He left a large estate of around 20,000 letters with 3,000 correspondence partners (Mittag-Leffler also kept copies of letters sent), most of which are in the Royal Library in Stockholm.

Others

In the past it was occasionally claimed that Alfred Nobel did not donate a Nobel Prize in mathematics because he feared out of personal animosity that Mittag-Leffler would then be forced to receive a prize as a leading Swedish mathematician. The truth is much more prosaic, as Lars Hörmander and Lars Gårding pointed out: Nobel never thought of giving a prize for mathematics because it was outside of his interests. The Fields Medal and, more recently, the Abel Prize act as a certain compensation .

According to Stubhaug, Mittag-Leffler was also instrumental in the fact that Marie Curie, together with her husband Pierre Curie and Henri Becquerel, was awarded the Nobel Prize in 1903 by persuading the committee to accept their nomination from the previous year. Mittag-Leffler had also campaigned for the Russian mathematician Sofia Kowalewskaja to be the first woman to receive a chair at a modern European university in Stockholm in 1884.

He also worked to ensure that Henri Poincaré got the Nobel Prize, in which he was unsuccessful, and also for Albert Einstein .

family

The writer Anne Charlotte Leffler is his sister.

See also

literature

Web links

Commons : Magnus Gösta Mittag-Leffler  - Album with pictures, videos and audio files

Individual evidence

  1. ↑ The small encyclopedia , Encyclios-Verlag, Zurich, 1950, volume 2, page 178
  2. ↑ Such as B. the early correspondence between Felix Klein and Henri Poincaré shows, this also led to obstacles in scientific exchange.
  3. ↑ Interview with Arild Stubhaug, Notices AMS 2005, pdf
  4. ↑ It was claimed that Mittag-Leffler had a relationship with Nobel's wife. Nobel lived outside Sweden for most of his life from 1865, which he rarely visited. He was also unmarried. [1]
  5. ^ Is there a Nobel Prize in Mathematics. In: Mathematical Intelligencer. Vol. 7, 1985, No. 3.
  6. ↑ Stubhaug, Interview, Notices AMS 2005
  7. ↑ Cordula Tollmien: "The most expensive element of the world", in: Charlotte Kerner (Ed.) Madame Curie and her sisters. Women who won the Nobel Prize, Beltz 1997, pp. 11–43, p. 34.
personal data
SURNAME Mittag-Leffler, Magnus Gösta
BRIEF DESCRIPTION Swedish mathematician
DATE OF BIRTH March 16, 1846
PLACE OF BIRTH Stockholm
DATE OF DEATH July 7, 1927
Place of death Djursholm