# Nachman Aronszajn

Nachman Aronszajn | |
---|---|

Born |
Warsaw, Poland | 26 July 1907

Died |
5 February 1980 72) Corvallis, Oregon, U.S. | (aged

Nationality | Polish American |

Fields | Mathematics |

Institutions | University of Kansas |

Alma mater |
University of Warsaw University of Paris |

Doctoral advisor |
Maurice René Fréchet Stefan Mazurkiewicz |

Doctoral students | W. Martin Greenlee |

Known for |
Aronszajn line Aronszajn–Smith theorem Aronszajn trees Moore–Aronszajn theorem |

**Nachman Aronszajn** (26 July 1907 – 5 February 1980^{[1]}) was a Polish American mathematician. Aronszajn's main field of study was mathematical analysis. He also contributed to mathematical logic.

## Life

An Ashkenazi Jew, Aronszajn received his Ph.D. from the University of Warsaw, in 1930, in Poland. Stefan Mazurkiewicz was his thesis advisor. He also received a Ph.D. from Paris University, in 1935; this time Maurice Fréchet was his thesis advisor. He joined the Oklahoma A&M faculty, but moved to the University of Kansas in 1951 with his colleague Ainsley Diamond after Diamond, a Quaker, was fired for refusing to sign a newly instituted loyalty oath.^{[2]} Aronszajn retired in 1977. He was a Summerfield Distinguished Scholar from 1964 to his death.

## Work

He introduced, together with Prom Panitchpakdi, the injective metric spaces under the name of "hyperconvex metric spaces". Together with Kennan T. Smith, Aronszajn offered proof of the Aronszajn–Smith theorem. Also, the existence of Aronszajn trees was proven by Aronszajn; Aronszajn lines, also named after him, are the lexicographic orderings of Aronszajn trees.

He also made a contribution to the theory of reproducing kernel Hilbert space. The Moore–Aronszajn theorem is named after him.^{[3]}

## References

- ↑ Kühn, Heidi, ed. (2004).
*Biographisch-literarisches Handwörterbuch der exakten Naturwissenschaften*. Wiley. p. 32. ISBN 3-527-40330-2. - ↑ Magill, K. D., Jr. (1996), "An interview with John Isbell",
*Topology Communications*,**1**(2). - ↑ Aronszajn, Nachman (1950). "Theory of Reproducing Kernels".
*Transactions of the American Mathematical Society*.**68**(3): 337–404. doi:10.2307/1990404.

## External links

- Nachman Aronszajn on Scientific Commons.
- Guide to the Nachman Aronszajn Collection – personal papers of Nachman Aronszajn, 1951–1977
- Nachman Aronszajn at the Mathematics Genealogy Project