Ernst Leonard Lindelöf

Ernst Leonard Lindelöf ( born March 7, 1870 in Helsingfors (Helsinki), † June 4, 1946 in Helsinki) was a Finnish mathematician.

He was the son of Leonard Lorenz Lindelöf (1827-1908), who from 1857 to 1874 there was a math professor after receiving his doctorate in Helsinki ( Helsingfors ), and then in the Ministry of Education. Also Lindelöf studied mathematics in Helsingfors from 1887 with stays abroad in 1891 in Stockholm and in 1893 /94, Paris. In 1893 he earned his doctorate under Hjalmar Mellin in Helsingfors ( Sur les systèmes complets et le calcul of the invariants of the différentiels groupes finis continus, Acta Soc. Scient. Fennicae, Volume 20, 1893) and was a lecturer after graduating in Helsingfors. In 1901, he attended the University of Göttingen. In 1902 he became associate professor in 1903 and professor in Helsingfors. In 1938, he went into retirement.

From 1907 he was an editor of Acta Mathematica and he was a member of the Finnish Academy of Sciences. He had in the Finnish mathematics beginning of the 20th century, which produced many outstanding function theorist, a central position and had a formative impact. His doctoral include Lars Ahlfors, Pekka MYRBERG and Rolf Nevanlinna (the son of a cousin of Lindelöf was ). His brother is the philosopher Uno Lorenz Lindelöf.

He made ​​important contributions to analysis, especially on complex analysis and the theory of differential equations.

After Ernst Leonard Lindelöf the Lindelöf space is named in topology, a topological space in which every cover by open sets contains a countable subset which is still a surplus.

Several mathematical theorems are named after Lindelöf, including the set of Picard - Lindelöf about existence and uniqueness of solutions of ordinary differential equations, the set of Phragmén - Lindelöf about the growth of holomorphic functions in certain areas (such as sectors or stripes) and the set of Lindelöf over asymptotic values ​​limited ( or normal ) of holomorphic functions in the unit disk. In analytic number theory there is the lindelöfsche conjecture about the growth of the Riemann zeta function on the critical line.

Lindelöf also dealt with Finnish history of mathematics and he is also known for his textbooks: reading his Introduction to the Analysis caused, for example, Rolf Nevanlinna that it turned to the study of mathematics.

Lindelöf was an outstanding violinist and played in his youth in a quartet with Jean Sibelius.

In addition, the asteroid ( 1407) Lindelöf was named after him.

Writings

• Le calcul of Résidus et ses applications à la théorie des fonctions, Paris, Gauthier -Villars, 1905, Reprint Chelsea, New York 1947, online and in the Project Gutenberg
• Introduction to Higher Analysis, Teubner 1934, 2nd edition 1950 ( according to the Swedish edition in 1912 translated into German by Egon Ullrich )