Christoffel Jacob Bouwkamp

Christoffel Jacob Bouwkamp (born June 26, 1915 in Hoogkerk , † February 23, 2003 in Eindhoven ) was a Dutch applied mathematician and theoretical physicist, known for research on diffraction theory .

Life

He studied mathematics, mechanics and theoretical physics at the University of Groningen with the doctoral exam cum laude in 1938. While still a student, he published five papers. In 1939/40 he did his military service. In 1941 he received his doctorate from Frits Zernike in Groningen with a thesis on diffraction at round holes (Theoretische en numeriekebehäling van de buiging door een ronde opening). Already in his dissertation he attached importance to an algorithmic treatment with strict accuracy estimates. He taught briefly in Groningen and in March 1941 went to the Philips Research Laboratories in Eindhoven, where he stayed for the rest of his career until his retirement in 1975, where he became group leader and, after his retirement, a consultant. He was also an associate professor for applied mathematics at the University of Utrecht (1955 to 1958) and at the TU Eindhoven (1958 to 1980).

At Philips he worked on antenna theory, among other things. An essay by Nicolaas Govert de Bruijn from 1946 is known about the poor position of the problem of optimal current distribution in a wire antenna. His main area of work that made him famous was diffraction theory, on which he published a large work in 1954. In it he also accounted for errors in treatment by Hans Bethe and Edward Thomas Copson . The dispute was led in the Mathematical Reviews, in which Bouwkamp was an often controversial colleague (reviewer from 1947 to 1980).

Since the 1940s he has been concerned with entertainment mathematics and has published about it, for example about the division of rectangles into squares (including the square of the square ) or about pentomino problems. He corresponded with William Tutte in the 1940s on the problem of dividing rectangles into squares and also used computers for this early on. His doctoral student AJW Duijvestijn (1927–1988) did his doctorate with him in 1962 in Eindhoven.

In 1960 he became a member of the Royal Netherlands Society of Sciences. He was a member of the American Mathematical Society since 1947 .

He was a passionate stamp and coin collector. He had been married to Alida Hendrika van der Veer since 1943 and had one daughter.

Kepler-Bouwkamp constant

The Kepler-Bouwkamp constant is named after him and Johannes Kepler . It is the radius of the boundary circle, which is obtained through the following boundary process: Write an equilateral triangle into a circle of radius 1, into which a circle, the circle an equilateral square, etc.

The value is: ${\ displaystyle \ prod _ {k = 3} ^ {\ infty} \ cos \ left ({\ frac {\ pi} {k}} \ right) = 0 {,} 1149420448 \ dots.}$

literature

J. Boersma, AT De Hoop: Passie voor precisie; In Memoriam Christoffel Jacob Bouwkamp (1915-2003) , Nieuw Archief voor Wiskunde, Series 5, Volume 4, September 2003, pp. 205-207
Jacques Haubrich: CJ Bouwkamp en de Squared Squares , Nieuw Archief voor Wiskunde, Series 5, Volume 4, December 2003, pp. 321–326
Philips Research Reports, Vol. 30, 1975, pp. 1-379. Special issue in honor of Bouwkamp with a list of publications up to 1975

Fonts

Diffraction theory, Reports on Progress in Physics, Volume 17, 1954, pp. 35-100
with Nicolaas Govert de Bruijn : The problem of optimum antenna current distribution , Philips Research Reports, Volume 1, 1946, pp. 135-158
On the freely vibrating circular disk and the diffraction by circular disks and holes , Physica, Volume 16, 1950, pp. 1-16
On the diffraction of electromagnetic waves by small circular disks and holes, Philips Research Reports, Volume 5, 1950, pp. 401-422
On Bethe's theory of diffraction by small holes, Philips Research Reports, Volume 5, 1950, pp. 321-332

Web links

Dutch biography of Adrianus T. De Hoop ( Memento from February 22, 2014 in the Internet Archive )
Biography at Squaring Net, English

Individual evidence

^ Polygon Inscribing, Mathworld
↑ Bouwkamp An Infinite Product , Indagationes Mathematicae, Volume 27, 1965, pp. 40-46

personal data
SURNAME	Bouwkamp, Christoffel Jacob
BRIEF DESCRIPTION	Dutch mathematician
DATE OF BIRTH	June 26, 1915
PLACE OF BIRTH	Hoogkerk
DATE OF DEATH	February 23, 2003
Place of death	Eindhoven

[1] Polygon Inscribing, Mathworld

[2] Bouwkamp An Infinite Product , Indagationes Mathematicae, Volume 27, 1965, pp. 40-46