**INHALTE**

## Horst Sachs 1927 - 2016

Many of you will be saddened to hear that Horst Sachs has died. He passed away on 25 April 2016, having turned 89 only a few weeks before, on 27 March. Horst Sachs was one of the pioneers of graph theory in Germany, and will be remembered as the founder of the graph theory school in Ilmenau, which served as an important link between east and west during the cold war and afterwards.

He received his PhD and Habilitation from the University of Halle, and was appointed full professor at the TU Ilmenau in 1963.

Horst Sachs is best known for his work in graph theory. More than a hundred scientific papers, among them the seminal book on graph spectra (with Doob and Cvetkovic), established his excellent international reputation. He also wrote an introduction into graph theory, which was the standard graph theory text in the eastern part of Germany for many years. Beside his work in pure mathematics, Horst Sachs successfully cooperated with chemists and physicists, and was interested in the history of mathematics.

After his retirement in 1992 until his last months he continued his research and showed up regularly at the institute.

Thomas Böhme - Jochen Harant - Matthias Kriesell - Michael Stiebitz