Leopold Fejér

Lipót (Leopold) Fejér
Left to right, standing: Frigyes Riesz, Béla Kerékjártó, Alfréd Haar, Gyula Kőnig, Rudolf Ortvay (), on chairs: József Kürschák, George David Birkhoff, O.D. Kellog, Lipót Fejér, sitting on the floor: Tibor Radó, István Lipka (), László Kalmár, Pál Szász ()
Born	(1880-02-09)9 February 1880 Pécs, Austria-Hungary
Died	15 October 1959(1959-10-15) (aged 79) Budapest, Hungary
Residence	Hungary
Nationality	Hungarian
Fields	Mathematics
Institutions	University of Pázmány Péter University of Berlin
Alma mater	University of Pázmány Péter
Doctoral advisor	Hermann Schwarz
Doctoral students	Paul Erdős John von Neumann Pál Turán George Pólya Tibor Radó László Kalmár Marcel Riesz Gábor Szegő Michael Fekete
Other notable students	Cornelius Lanczos
Known for	Harmonic analysis Fourier series.

Lipót Fejér (or Leopold Fejér, Hungarian pronunciation: [ˈfɛjeːr]; 9 February 1880 – 15 October 1959) was a Hungarian born Jewish mathematician. Fejér was born Leopold Weiss, and changed to the Hungarian name Fejér around 1900.

Fejér studied mathematics and physics at the University of Budapest and at the University of Berlin, where he was taught by Hermann Schwarz. In 1902 he earned his doctorate from Eötvös Loránd University. From 1902 to 1905 Fejér taught at the University of Pázmány Péter and from 1905 until 1911 he taught at Franz Joseph University in Kolozsvár in Austria-Hungary (now Cluj-Napoca in Romania). In 1911 Fejér was appointed to the chair of mathematics at the University of Budapest and he held that post until his death. He was elected corresponding member (1908), member (1930) of the Hungarian Academy of Sciences.

During his period in the chair at Budapest Fejér led a highly successful Hungarian school of analysis. He was the thesis advisor of mathematicians such as John von Neumann, Paul Erdős, George Pólya and Pál Turán.