Oskar Perron

Oskar Perron (7 May 1880 – 22 February 1975) was a German mathematician.

He was a professor at the University of Heidelberg from 1914 to 1922 and at the Ludwig-Maximilians-Universität München from 1922 to 1951. He made numerous contributions to differential equations and partial differential equations, including the Perron method to solve the Dirichlet problem for elliptic partial differential equations. He wrote an encyclopedic book on continued fractions Die Lehre von den Kettenbrüchen. He introduced Perron's paradox to illustrate the danger of assuming that the solution of an optimization problem exists:

Let N be the largest positive integer. If N > 1, then N > N, contradicting the definition of N. Hence N = 1.

• Über die Drehung eines starren Körpers um seinen Schwerpunkt bei Wirkung äußerer Kräfte, Dissertation, Ludwig-Maximilians-Universität München, 1902
• Grundlagen für eine Theorie der Jacobischen Kettenbruchalgorithmus, Habilitationsschrift Leipzig 1906
• Die Lehre von den Kettenbrüchen, 2 vols., 1913, 3rd edn. Teubner Verlag 1954 (vol. 1 Elementare Kettenbrüche, vol. 2 analytische und funktionentheoretische Kettenbrüche)
• Irrationalzahlen, 1921, 2nd edn. 1939, 4th edn. de Gruyter, Berlin 1960
• Algebra I, II, Sammlung Göschen 1927, 3rd edn, 1951
• with Evelyn Frank: Frank, Evelyn; Perron, Oskar (1954). "Remark on a certain class of continued fractions". Proc. Amer. Math. Soc. 5 (2): 270–283. doi:10.1090/s0002-9939-1954-0061185-4. MR 0061185.
• Nichteuklidische Elementargeometrie der Ebene, Teubner, Stuttgart 1962