Josip Plemelj

Josip Plemelj (* December 11, 1873 in Bled, † May 22 1967 in Ljubljana ) was a Slovene mathematician and university professor.

Life

Plemelj grew up in poverty. His mathematical talent was recognized early and he was given a good education allows. From 1894 to 1898 he studied at the University of Vienna where he phil at Gustav von Escherich Dr.. doctorate. Then he was at the Friedrich- Wilhelms- University of Berlin and the Georg-August -Universität Göttingen.

Habilitated in 1902 in Vienna, he taught as a Privatdozent. In 1907 he was appointed professor at the Franz Joseph's University Chernivtsi. In World War I he was expelled in 1917 from there.

1919 Plemelj was the first rector of the reopened University of Ljubljana, whose expansion was an important task in the early years of the new Kingdom of Serbs, Croats and Slovenes to a Slovenian university. He worked as a mathematics professor until his retirement in 1957 at the age of 83 years. Throughout his career he received numerous awards, including the Richard Lieben Prize, inclusion in the Yugoslav, Slovenian and the Bavarian Academy of Sciences (1954 ) and an honorary doctorate from the University of Ljubljana.

Plemelj worked mainly in the field of differential and integral equations. At the suggestion of David Hilbert in Göttingen, he was one of the first who made ​​important progress in the theory of Fredholm operators. His name is also associated with the Plemelj - Sokhotsky formulas that play a role in various applications of singular integral equations. Also worth mentioning is Plemeljs particularly elegant proof of Fermat 's conjecture in the case n = 5

His ostensible solution of Hilbert's 21st problem was disproved in 1989 by Andrei Bolibruch. Plemelj had then proved himself an attempted solution of Ludwig Schlesinger to be incomplete.