Nicolaas Govert de Bruijn

Nicolaas Govert de Bruijn
Born	(1918-07-09)9 July 1918 The Hague
Died	17 February 2012(2012-02-17) (aged 93) Nuenen
Nationality	Dutch
Fields	Mathematics
Institutions	Eindhoven University of Technology
Alma mater	Vrije Universiteit Amsterdam
Doctoral advisor	Jurjen Ferdinand Koksma
Doctoral students	Matheus Hautus Antonius Levelt Robert Nederpelt Lazarom Johannes Runnenburg Stan Ackermans
Known for	De Bruijn sequence

Nicolaas Govert "Dick" de Bruijn (9 July 1918 – 17 February 2012) was a Dutch mathematician, affiliated as professor emeritus with the Eindhoven University of Technology. He received his Ph.D. in 1943 from Vrije Universiteit Amsterdam.

De Bruijn covered many areas of mathematics. He is especially noted for the discovery of the De Bruijn sequence. He is also partly responsible for the De Bruijn–Newman constant, the De Bruijn–Erdős theorem (in both incidence geometry and graph theory) and the BEST theorem. He wrote one of the standard books in advanced asymptotic analysis (De Bruijn, 1958). De Bruijn also worked on the theory of Penrose tilings. In the late sixties, he designed the Automath language for representing mathematical proofs, so that they could be verified automatically (see automated theorem checking). Shortly before his death, he had been working on models for the human brain.

Early life

De Bruijn was born in The Hague, Netherlands on July 9, 1918. De Bruijn's father owned a paint shop and his family had eight children. He attended an elementary school in The Hague, Netherlands from 1924 to 1930. He then went on to a secondary school called hogere burgerschool, HBS where he studied four years there after graduating in 1934. He finished the 5 year program in HBS in just 4 years. After completing his examinations to finish secondary school, de Bruijn failed to get a job or a scholarship due to his young age. He also couldn't find an appropriate job due to the Great Depression in the 1930s. He then took two years to learn mathematics on his own in which he received two mathematical teaching certificates.

College career

De Bruijn received an interest-free advanced to study mathematics at the Leiden University due to his teaching certificate he achieved at the age of 18. De Bruijn was particularly inspired by a lecturer H.D. Kloosterman, who was a large part of teaching to first and second year students at Leiden University. De Bruijn remembered the lectures Kloosterman gave on Lebesgue integrals, linear operators in Hilbert spaces, Group Theory, and Number Theory. Kloosterman gave lectures on these subjects from scratch which pleased De Bruijn. Klossterman stated he hardly ever seen a student like De Bruijn who formulated so precisely during De Bruijn's time at Leiden University. De Bruijn stated in his In Memoriam for Kloosterman "... from Kloosterman I inherited his love for precision and his love for correct mathematical language. Things not to be vague in order to be interesting. It was his style to be careful, precise, clear, patient, right to the goal, never a superfluous word". From 1939 to 1944, De bruijn was continuing his studies as a Ph.D degree in Leiden as well as supporting himself as an assistant at the Technische Hogeschool in Delft. Right after De Buijn took his doctorate exams in 1940, classes were suspended by the German occupiers because of the student protests over the discharge of Jewish Professors. Leiden University stopped awarding degrees during that time.

Mathematical career

Right after De Bruijn got his Ph.D, he took a research job at Philips NatLab research center in Eindhoven from 1944-1946. In 1946, he returned back to Delft as a Professor. Then in 1952 he was appointed as a professor at University of Amsterdam. Despite the prestige of University of Amsterdam, which had been the center for Dutch Mathematics for decades, J.J.Seidel managed to lure De Bruijn to the Technische Hogeschool Eindhoven (Eindhoven University of Technology) in 1960. Seidel, De Bruijn’s former fellow student and friend at Leiden University, had organized a new mathematics department there. In this fresh and expanding environment, De Bruijn had great freedom in his research topics. The mathematics department grew in eminence; by 1972, four of the ten KNAW (Royal Netherlands Academy of Arts and Sciences) members in mathematics worked in that department. De Bruijn was one of the members and the other three members were C. J. Bouwkamp,E. W. Dijkstra, and J. H. van Lint.
De Bruijn was a respected mathematician throughout his career, with almost 200 articles in journals and several books. He started as a specialist in analytic number theory, which led to an early communication with P. Erdős from 1948. In those years, he found a paper by G. Pólya in the collection of L. O. Blumenthal in the extensive mathematical library of Delft University, and he began communicating with Pólya. This led to personal contact between De Bruijn and Pólya,cumulating in the so-called Po´lya-de Bruijn enumeration, a famous result in combinatorics.

Gradually de Bruijn’s interest grew wider to include combinatorics, asymptotics, function theory, optimal control, Fourier theory, type theory, and quasicrystals. De Bruijn’s name has been attached to several mathematical notions, such as de Bruijn cycles and de Bruijn graphs, de Bruijn-Newman constant in Fourier theory, one Erdős-de Bruijn theorem about coloring of graphs and another about finite geometry, de Bruijn indices and de Bruijn notation in typed lambda calculus, and the de Bruijn criterion in type theory.

Death

Nicolaas Govert de Bruijn died on February 17, 2012 in Nuenen, Netherlands. He was 93 years of age when he died.

Publications

• de Bruijn, Asymptotic Methods in Analysis, North-Holland, Amsterdam, 1958.

See also

• De Bruijn graph
• De Bruijn index
• De Bruijn notation
• De Bruijn tiling
• De Bruijn's theorem
• Dickman–De Bruijn function
• Eulerian path

External links

• Official website
• Nicolaas Govert de Bruijn at the Mathematics Genealogy Project
• Nicolaas Govert de Bruijn's obituary