Magnus Gustaf (Gösta) Mittag-Leffler

Gösta Mittag-Leffler
Gösta Mittag-Leffler
Born	16 March 1846
Died	7 July 1927(1927-07-07) (aged 81) Djursholm
Citizenship	Swedish
Fields	Mathematics
Alma mater	Uppsala University (Ph.D., 1872)
Thesis	Om skiljandet af rötterna till en synektisk funktion af en variabel (1872)
Doctoral advisor	Göran Dillner ()
Doctoral students	Ivar Fredholm Hjalmar Mellin

Magnus Gustaf (Gösta) Mittag-Leffler (16 March 1846 – 7 July 1927) was a Swedish mathematician. His mathematical contributions are connected chiefly with the theory of functions, which today is called complex analysis.

Mittag-Leffler was born in , son of the school principal John Olof Leffler and Gustava Wilhelmina Mittag; he later added his mother's maiden name to his paternal surname. His sister was the writer Anne Charlotte Leffler. He matriculated at Uppsala University in 1865, completed his Ph.D. in 1872 and became docent at the university the same year. He was also curator (chairman) of the (1872–1873). He next traveled to Paris, Göttingen and Berlin, studying under Weierstrass in the latter place. He then took up a position as professor of mathematics (as successor to Lorenz Lindelöf) at the University of Helsinki from 1877 to 1881 and then as the first professor of mathematics at the (the later ); he was president of the college from 1891 to 1892 and retired from his chair in 1911. Mittag-Leffler went into business and became a successful businessman in his own right, but an economic collapse in Europe wiped out his fortune in 1922.

He was a member of the Royal Swedish Academy of Sciences (1883), the Finnish Society of Sciences and Letters (1878, later honorary member), the Royal Swedish Society of Sciences in Uppsala, the Royal Physiographic Society in Lund (1906) and about 30 foreign learned societies, including the Royal Society of London (1896) and Académie des sciences in Paris. He held honorary doctorates from the University of Oxford and several other universities.