Person: Collatz, Lothar
Lothar Collatz was a German mathematician who worked in numerical analysis and is best known for the eponymous "3_x_ + 1 problem".
Mathematical Profile (Excerpt):
 Collatz was awarded his doctorate in 1935 for his dissertation Das Differenzenverfahren mit höherer Approximation für lineare Differentialgleichunge Ⓣ(Difference methods with higher approximation for linear differential equations).
 Many will know the name of Collatz today because of the "Collatz problem".
 The Collatz problem is simple to state.
 In 1943 Collatz was appointed to a professorship at the Technical University of Hanover.
 MathSciNet lists 238 items under Collatz' name.
 Collatz began publishing important books early in his career.
 Later texts by Collatz include Optimization problems (1975) and Differential equations (1986), the second of these being an English translation of an earlier German book.
 Collatz received many honours for his contributions including election to the German Academy of Scientists Leopoldina, the academy at Bologna and that at Modena.
Born 6 July 1910, Arnsberg, Westphalia, Germany. Died 26 September 1990, Varna, Bulgaria.
View full biography at MacTutor
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Origin Germany
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References
Adapted from other CC BYSA 4.0 Sources:
 O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive