Johan Jacob Seidel 1919-2001
نویسندگان
چکیده
On May 8 2001, Jaap Seidel passed away. This volume of the European Journal of Combinatorics is dedicated to his memory. Jaap Seidel loved Mathematics. He wanted to learn it, to understand it, and most of all to teach it. In his courses and personal contacts he was very inspiring. Many mathematicians, especially young ones, were influenced by Jaap. Besides being a teacher, he was also very interested in what other researchers were doing. He always tried to find links to subjects he had been working on. Jaap’s work makes connections with several branches in mathematics, and he had struck friendships with mathematicians all over the world. He has been called an ambassador of mathematics. The paper that illustrates best Jaap’s way of making connections is probably: Line Graphs, Root Systems and Elliptic Geometry (with Cameron, Goethals, and Shult) from 1976. This work includes the famous characterization of graphs with least eigenvalue −2, but equally importantly it connects graph theory with geometry and algebra. An older
منابع مشابه
Seidel Signless Laplacian Energy of Graphs
Let $S(G)$ be the Seidel matrix of a graph $G$ of order $n$ and let $D_S(G)=diag(n-1-2d_1, n-1-2d_2,ldots, n-1-2d_n)$ be the diagonal matrix with $d_i$ denoting the degree of a vertex $v_i$ in $G$. The Seidel Laplacian matrix of $G$ is defined as $SL(G)=D_S(G)-S(G)$ and the Seidel signless Laplacian matrix as $SL^+(G)=D_S(G)+S(G)$. The Seidel signless Laplacian energy $E_{SL^+...
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عنوان ژورنال:
- Eur. J. Comb.
دوره 25 شماره
صفحات -
تاریخ انتشار 2004