Johan Jacob Seidel

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Jaap Seidel around 1985

Johan Jacob "Jaap" Seidel (born August 19, 1919 in The Hague ; † May 8, 2001 in Eindhoven ) was a Dutch mathematician who dealt with geometry and graph theory . He was a professor at the TU Eindhoven .

Life

Seidel went to the city high school in The Hague and studied at the University of Leiden from 1937 , where he was a student of Hendrik Kloosterman and graduated in 1940. After the university was closed under German occupation, he studied at the Free University of Amsterdam with Johannes Haantjes . His studies were interrupted when he was drafted into forced labor in a factory near Berlin. He escaped and then hid underground. From 1946 he taught at the Vossius Gymnasium in Amsterdam and at the same time wrote his dissertation with Haantjes and received his doctorate at the University of Leiden in 1948 (De congruentie-orde van het elliptische vlak, The congruence order of the elliptical plane). In 1950 he became a lecturer at the University of Delft and in 1954 he organized the entertainment program for the International Congress of Mathematicians in Amsterdam , for which he organized an exhibition by MC Escher . In 1955 he was on a study visit to Rome and represented the sick Haantjes in Leiden and in 1956 he became professor and head of the mathematics faculty at the newly founded TU Eindhoven.

In Eindhoven he turned to graph theory, focusing particularly on strongly regular graphs and block diagrams and, with Jacobus van Lint, in 1966 introduced the adjacency matrix named after him , a variant of the usual adjacency matrix with entries 0 in the diagonal, −1 if the nodes are connected and +1 if not.

Fonts

  • D. G Corneil, R. Mathon: Geometry and Combinatorics , Selected Works of JJ Seidel, Academic Press, 1991

literature

  • A. Blokhuis, J. Van Lint: In memoriam Johan Jacob Seidel (Dutch), Nieuw Arch. Wiskdunde, Series 5, Volume 2, 2001, pp. 207-209.
  • Nicolaas Govert de Bruijn : Jaap Seidel, a friend, ibid, pp. 204-206
  • de Bruijn: Jaap Seidel 80, in: Special issue dedicated to Dr Jaap Seidel on the occasion of his 80th birthday, Oisterwijk, 1999, Designs Codes Cryptography, Volume 21, 2000, pp. 7-10.

Web links

Individual evidence

  1. ^ Johan Jacob Seidel in the Mathematics Genealogy Project (English)Template: MathGenealogyProject / Maintenance / id used
  2. ↑ Seidel, Van der Lint: Equilateral point sets in elliptic geometry , Indagationes Mathematicae, Volume 28 (= Proc. Kon. Ned. Aka. Wet. Ser. A, Volume 69), 1966, pp. 335-348. pdf
personal data
SURNAME Seidel, Johan Jacob
ALTERNATIVE NAMES Seidel, Jaap
BRIEF DESCRIPTION Dutch mathematician
DATE OF BIRTH August 19, 1919
PLACE OF BIRTH The hague
DATE OF DEATH May 8, 2001
Place of death Eindhoven