József Kürschák

József Kürschák
Left to right, standing: Frigyes Riesz, Béla Kerékjártó, Alfréd Haar, Dénes 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(1864-03-14)14 March 1864
Died26 March 1933(1933-03-26) (aged 69)
Alma materTechnical University of Budapest
Scientific career
FieldsMathematics
InstitutionsTechnical University of Budapest
Doctoral studentsDénes Kőnig

József Kürschák (14 March 1864 – 26 March 1933) was a Hungarian mathematician noted for his work on trigonometry and for his creation of the theory of valuations. He proved that every valued field can be embedded into a complete valued field which is algebraically closed. In 1918 he proved that the sum of reciprocals of consecutive natural numbers is never a natural number. Extending Hilbert's argument, he proved that everything that can be constructed using a ruler and a compass, can be constructed by using a ruler and the ability to copy a fixed segment. He was elected a member of the Hungarian Academy of Sciences in 1897. He was one of the main organisers of mathematics competitions, for example, Eötvös Loránd mathematics competition.