Nachman Aronszajn

Nachman Aronszajn was a Polish American mathematician, born on 26 July 1907, whose main field of study was mathematical analysis, where he systematically developed the concept of reproducing kernel Hilbert space, and who also contributed to mathematical logic. He received his Ph.D. from the University of Warsaw in 1930 under Stefan Mazurkiewicz and another from Paris University in 1935 under Maurice Fréchet. He moved to the University of Kansas in 1951 and retired in 1977. With Prom Panitchpakdi he introduced injective metric spaces under the name of hyperconvex metric spaces, and he proved the existence of Aronszajn trees; the Moore-Aronszajn theorem is also named after him. He died on 5 February 1980.