Hendrik Willem Lenstra Jr. (born 16 April 1949, Zaandam) is a Dutch

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

Biography

Lenstra received his

doctorate A doctorate (from Latin ''docere'', "to teach"), doctor's degree (from Latin ''doctor'', "teacher"), or doctoral degree is an academic degree awarded by universities and some other educational institutions, derived from the ancient formalism ''l ...

from the

University of Amsterdam The University of Amsterdam (abbreviated as UvA, nl, Universiteit van Amsterdam) is a public research university located in Amsterdam, Netherlands. The UvA is one of two large, publicly funded research universities in the city, the other being ...

in 1977 and became a professor there in 1978. In 1987 he was appointed to the faculty of the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...

; starting in 1998, he divided his time between Berkeley and the University of Leiden, until 2003, when he retired from Berkeley to take a full-time position at Leiden. Three of his brothers, Arjen Lenstra, Andries Lenstra, and

Jan Karel Lenstra Jan Karel Lenstra (born 19 December 1947, in Zaandam) is a Dutch mathematician and operations researcher, known for his work on scheduling algorithms, local search, and the travelling salesman problem. Lenstra received his Ph.D. from the Univers ...

, are also mathematicians. Jan Karel Lenstra is the former director of the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

Centrum Wiskunde & Informatica The (abbr. CWI; English: "National Research Institute for Mathematics and Computer Science") is a research centre in the field of mathematics and theoretical computer science. It is part of the institutes organization of the Dutch Research Cou ...

(CWI). Hendrik Lenstra was the Chairman of the Program Committee of the

International Congress of Mathematicians The International Congress of Mathematicians (ICM) is the largest conference for the topic of mathematics. It meets once every four years, hosted by the International Mathematical Union (IMU). The Fields Medals, the Nevanlinna Prize (to be rename ...

in 2010.

Scientific contributions

Lenstra has worked principally in

computational number theory In mathematics and computer science, computational number theory, also known as algorithmic number theory, is the study of computational methods for investigating and solving problems in number theory and arithmetic geometry, including algorithms ...

. He is well known for: * Co-discovering of the

Lenstra–Lenstra–Lovász lattice basis reduction algorithm The Lenstra–Lenstra–Lovász (LLL) lattice basis reduction algorithm is a polynomial time lattice reduction algorithm invented by Arjen Lenstra, Hendrik Lenstra and László Lovász in 1982. Given a basis \mathbf = \ with ''n''-dimensional inte ...

(in 1982); * Developing an polynomial-time algorithm for solving a feasibility Integer programming problem when the number of variables is fixed (in 1983); * Discovering the

elliptic curve factorization The Lenstra elliptic-curve factorization or the elliptic-curve factorization method (ECM) is a fast, sub-exponential running time, algorithm for integer factorization, which employs elliptic curves. For general-purpose factoring, ECM is the thi ...

method (in 1987); * Computing all solutions to the inverse Fermat equation (in 1992); * The Cohen–Lenstra heuristics - a set of precise conjectures about the structure of class groups of quadratic fields.

Awards and honors

In 1984 Lenstra became member of the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed ...

. He won the Fulkerson Prize in 1985 for his research using the

geometry of numbers Geometry of numbers is the part of number theory which uses geometry for the study of algebraic numbers. Typically, a ring of algebraic integers is viewed as a lattice in \mathbb R^n, and the study of these lattices provides fundamental information ...

to solve integer programs with few variables in time polynomial in the number of constraints. He was awarded the

Spinoza Prize The Spinoza Prize ( nl, Spinozapremie) is an annual award of 2.5 million euro, to be spent on new research given by the Dutch Research Council (NWO). The award is the highest scientific award in the Netherlands. It is named after the philosopher ...

in 1998, and on 24 April 2009 he was made a Knight of the Order of the Netherlands Lion. In 2009, he was awarded a Gauss Lecture by the

German Mathematical Society The German Mathematical Society (german: Deutsche Mathematiker-Vereinigung, DMV) is the main professional society of German mathematicians and represents German mathematics within the European Mathematical Society (EMS) and the International Mathe ...

. In 2012 he became a fellow of the

American Mathematical Society The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, and serves the national and international community through its publications, meetings, ...

.List of Fellows of the American Mathematical Society
retrieved 2013-01-27.

Publications

* ''Euclidean Number Fields.'' Parts 1-3, Mathematical Intelligencer 1980 * with A. K. Lenstra: ''Algorithms in Number Theory.'' pp. 673–716, In Jan van Leeuwen (ed.): ''Handbook of Theoretical Computer Science, Vol. A: Algorithms and Complexity.'' Elsevier and MIT Press 1990, , .

Bulletin of the AMS, vol. 26, 1992, pp. 211–244.
''Primality testing algorithms.''
Séminaire Bourbaki 1981. * with Stevenhagen
''Artin reciprocity and Mersenne Primes.''
Nieuw Archief for Wiskunde 2000. * with Stevenhagen: '' Chebotarev and his density theorem.'' Mathematical Intelligencer 1992 (Online at Lenstra's Homepage).
''Profinite Fibonacci Numbers'', December 2005, PDF

References

External links

* * , Homepage at the Leiden Mathematisch Instituut * {{DEFAULTSORT:Lenstra, Hendrik 1949 births Living people 20th-century Dutch mathematicians 21st-century Dutch mathematicians Members of the Royal Netherlands Academy of Arts and Sciences Number theorists Spinoza Prize winners University of Amsterdam alumni University of Amsterdam faculty Leiden University faculty University of California, Berkeley College of Letters and Science faculty Fellows of the American Mathematical Society Dutch expatriates in the United States People from Zaanstad