Heiko Harborth (born 11 February 1938, in Celle, Germany)[Harborth's web site http://www.mathematik.tu-bs.de/harborth/ . Accessed 14 May 2009.] is Professor of Mathematics at Braunschweig University of Technology, 1975–present, and author of more than 188 mathematical publications.[AMS MathSciNet http://www.ams.org/mathscinet . Accessed 14 May 2009.] His work is mostly in the areas of number theory, combinatorics and discrete geometry, including graph theory.
Career
Harborth has been an instructor or professor at Braunschweig University of Technology since studying there and receiving his PhD in 1965 under Hans-Joachim Kanold.
Harborth is a member of the New York Academy of Sciences, Braunschweigische Wissenschaftliche Gesellschaft, the Institute of Combinatorics and its Applications, and many other mathematical societies. Harborth currently sits on the editorial boards of Fibonacci Quarterly,
Geombinatorics, . He served as an editor of Mathematische Semesterberichte from 1988 to 2001. Harborth was a joint recipient (with Stephen Milne) of the 2007
Euler Medal.
Mathematical work
Harborth's research ranges across the subject areas of
combinatorics,
graph theory, discrete geometry, and
number theory. In 1974, Harborth solved the
penny graph problem,
[Heiko Harborth, Lösung zu Problem 664A, Elem. Math. 29 (1974), 14–15.] determining the maximum number of edges possible in a unit coin graph on n vertices. In 1986, Harborth presented the graph that would bear his name, the
Harborth graph. It is the smallest known example of a 4-
regular graph matchstick graph. It has 104 edges and 52 vertices.
In connection with the happy ending problem, Harborth showed that, for every finite set of ten or more points in general position in the plane, some five of them form a convex pentagon that does not contain any of the other points.
Harborth's conjecture[; ;
.] posits that every planar graph admits a straight-line embedding in the plane where every edge has integer length. This open question () is a stronger version of Fáry's theorem. It is known to be true for .[.]
In number theory, the Stolarsky–Harborth constant
Private life
Harborth married Karin Reisener in 1961, and they had two children. He was widowed in 1980. In 1985 he married Bärbel Peter and with her has three stepchildren.
Notes
