Voltage droop

2013-09-05T08:40:54Z

220.225.251.145:

{{Infobox scientist
| name = Hans Heilbronn
| birth_name = Hans Arnold Heilbronn
| image = 
| image_size =
| caption =
| birth_date = {{birth date|1908|10|08|df=y}}
| birth_place = [[Berlin]]
| death_date = {{death date and age|1975|04|28|1908|10|08|df=y}}
| death_place = [[Toronto]]
| nationality = [[German Canadian]]
| fields = [[Mathematics]]
| workplaces = [[University of Toronto]]<br>[[University of Cambridge]]<br>[[University of Bristol]]
| alma_mater = [[University of Göttingen]]
| doctoral_advisor = [[Edmund Landau]]<ref name="mathgene"/>
| doctoral_students = Thomas Callahan<br>Inder Chowla<br>[[Albrecht Fröhlich]]<ref name="mathgene"/>
| known_for =
| awards = [[Fellow of the Royal Society]]<ref name="frs">{{cite doi|10.1098/rsbm.1976.0005}}</ref>
}}
'''Hans Arnold Heilbronn''' [[Royal Society|FRS]]<ref name="frs"/> (8 October 1908 – 28 April 1975) was a [[mathematician]].<ref name="mathgene">{{MathGenealogy |id=46841}}</ref><ref name="odnb">{{cite doi|10.1093/ref:odnb/51633 }}</ref><ref name="mactutor">{{MacTutor Biography|id=Heilbronn}}</ref>

==Education==
He was born into a [[Germans|German]]-[[Jewish]] family. He was a student at the universities of [[Berlin]], [[Freiburg]] and [[Göttingen]], where he met [[Edmund Landau]], who supervised his doctorate. In his thesis, he improved a result of [[Guido Hoheisel|Hoheisel]] on the size of [[prime gap]]s.

==Life==
Heilbronn fled Germany for Britain in 1933 due to the rise of [[Nazism]]. He arrived in [[Cambridge]], then found accommodation in [[Manchester]] and eventually was offered a position at [[Bristol University]], where he stayed for about one and a half years. There he proved that the [[class number (number theory)|class number]] of the [[number field]] <math>\mathbb{Q}(\sqrt{-d})</math> tends to plus infinity as <math>d</math> does, as well as, in collaboration with [[Edward Linfoot]], that there are at most ten quadratic [[number field]]s of the form <math>\mathbb{Q}(\sqrt{-d})</math>, <math>d</math> a natural number, with class number 1. On invitation of [[Louis Mordell]] he moved back to [[Manchester]] in 1934, but left again only one year later, accepting the Bevan Fellowship at [[Trinity College, Cambridge]]. In Cambridge Heilbronn published several joint papers with [[Harold Davenport]], in one of which they devised a new variant of the [[Hardy-Littlewood circle method]], now sometimes referred to as the Davenport-Heilbronn method, proving that for any indefinite diagonal form <math>f</math> of degree <math>k</math> in more than <math>n=2^k</math> variables whose coefficients are not all in rational ratio there exists <math>x</math> in <math>\mathbb{Z}^n</math> such that <math>|f(x)|</math> is arbitrarily small. During the [[Second World War]] he was briefly [[internment|interned]] as an enemy alien but released to serve in the [[British Army]]. In 1946 he returned to Bristol, becoming Henry Overton Wills Professor of Mathematics. He was elected a [[Fellow of the Royal Society]] in 1951 and was president of the [[London Mathematical Society]] from 1959 to 1961.

Heilbronn and his wife moved to North America in 1964. He stayed at the [[California Institute of Technology]] for a while, then moved on to [[Toronto]], where he was Professor of Mathematics at the [[University of Toronto]] from 1964 to 1975. He became a [[Canadian]] citizen in 1970.

His PhD students include Inder Chowla and [[Albrecht Fröhlich]].<ref name="mathgene"/>

==See also==
*[[Class number problem]]
*[[Deuring–Heilbronn phenomenon]]
*[[Heilbronn triangle problem]]

== References ==
{{reflist}}

{{Authority control|VIAF=49299145}}

{{Persondata 
| NAME = Heilbronn, Hans
| ALTERNATIVE NAMES =
| SHORT DESCRIPTION = German mathematician
| DATE OF BIRTH = 8 October 1908
| PLACE OF BIRTH = [[Berlin]]
| DATE OF DEATH = 28 April 1975
| PLACE OF DEATH = [[Toronto]]
}}
{{DEFAULTSORT:Heilbronn, Hans}}
[[Category:1908 births]]
[[Category:1975 deaths]]
[[Category:20th-century mathematicians]]
[[Category:German mathematicians]]
[[Category:German Jews]]
[[Category:British Jews]]
[[Category:Canadian mathematicians]]
[[Category:20th-century British mathematicians]]
[[Category:Number theorists]]
[[Category:Academics of the University of Bristol]]
[[Category:Fellows of Trinity College, Cambridge]]
[[Category:University of Toronto faculty]]
[[Category:Fellows of the Royal Society]]
[[Category:People who emigrated to escape Nazism]]
[[Category:Jews who emigrated to the United Kingdom to escape Nazism]]
[[Category:German emigrants to Canada]]
[[Category:Canadian Jews]]

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