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# Lothar Collatz

Lothar Collatz (July 6, 1910, Arnsberg, Westphalia – September 26, 1990, Varna, Bulgaria) was a German mathematician. In 1937 he posed the famous Collatz conjecture, which remains unsolved.

The Collatz-Wielandt formula for positive matrices important in the Perron–Frobenius theorem is named after him.

Collatz studied at different universities in Germany including the University of Berlin under Alfred Klose, receiving his doctorate in 1935 for a dissertation entitled Das Differenzenverfahren mit höherer Approximation für lineare Differentialgleichungen (The finite difference method with higher approximation for linear differential equations).

For his many contributions to the field, Collatz had many honors bestowed upon him in his lifetime, including:

election to the German Academy of Scientists Leopoldina, the academy at Bologna and Modena in Italy.

honorary member of the Hamburg Mathematical Society

honorary degrees by the University of São Paulo, the Technical University of Vienna, the University of Dundee in Scotland, Brunel University in England, the Technical University of Hanover, and the Technical University of Dresden.

He died in Varna, Bulgaria, while attending a mathematics conference.

References

Lothar Collatz (July 6, 1910–September 26, 1990), Journal of Approximation Theory, Vol 65, Issue 1, April 1991, Page II by Günter Meinardus and Günther Nürnberger

Collatz, Lothar (1942), "Einschließungssatz für die charakteristischen Zahlen von Matrize", Mathematische Zeitschrift 48 (1): 221–226, doi:10.1007/BF01180013

Bibliography

J Albrecht, P Hagedorn and W Velte, Lothar Collatz (German), Numerical treatment of eigenvalue problems, Vol. 5, Oberwolfach, 1990 (Birkhäuser, Basel, 1991), viii-ix.

R Ansorge, Lothar Collatz (6 July 1910-26 September 1990) (German), Mitt. Ges. Angew. Math. Mech. No. 1 (1991), 4-9.

U Eckhardt, Der Einfluss von Lothar Collatz auf die angewandte Mathematik, Numerical mathematics, Sympos., Inst. Appl. Math., Univ. Hamburg, Hamburg, 1979 (Birkhäuser, Basel-Boston, Mass., 1979), 9-23.

L Elsner and K P Hadeler, Lothar Collatz - on the occasion of his 75th birthday, Linear Algebra Appl. 68 (1985), vi; 1-8.

R B Guenther, Obituary : Lothar Collatz, 1910-1990, Aequationes Math. 43 (2-3) (1992), 117-119.

H Heinrich, Zum siebzigsten Geburtstag von Lothar Collatz, Z. Angew. Math. Mech. 60 (5) (1980), 274-275.

G Meinardus, G Nürnberger, Th Riessinger and G Walz, In memoriam : the work of Lothar Collatz in approximation theory, J. Approx. Theory 67 (2) (1991), 119-128.

G Meinardus and G Nürnberger, In memoriam : Lothar Collatz (July 6, 1910-September 26, 1990), J. Approx. Theory 65 (1) (1991), i; 1-2.

J R Whiteman, In memoriam : Lothar Collatz, Internat. J. Numer. Methods Engrg. 31 (8) (1991), 1475-1476.

External links

O'Connor, John J.; Robertson, Edmund F., "Lothar Collatz", MacTutor History of Mathematics archive, University of St Andrews.

Lothar Collatz at the Mathematics Genealogy Project

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