### We mourn the death of Prof. Dr. Wilhelm Niethammer

Wilhelm Niethammer, professor emeritus at the University of Karlsruhe, passed away at his home in Karlsruhe on March 17, 2023. Born in

Unterjettingen, a small village close to Stuttgart, he studied mathematics with minor in physics at the universities of Stuttgart and

Tuebingen, where his mathematical interests were strongly influenced by the “three K’s” (E. Kamke, H. Kneser, K. Knopp). Originally, he

wanted to become a teacher but then changed to academia. He completed his doctoral thesis under the supervision of Karl Zeller in 1964.

In this dissertation, he applied algorithms and ideas from complex analysis to the iterative solution of linear systems of algebraic equations,

a topic which he was concerned with throughout his scientific life.

Wilhelm Niethammer continued this academic career at the University of Bochum. In 1970, he was appointed professor at the University of

of Mannheim. In 1978, he accepted the call to the professorship “Numerische Mathematik und Grossrechenanlagen” at the University of

Karlsruhe, where he headed the “Institut fuer Praktische Mathematik” until his retirement in 2002.

Wilhelm Niethammer was well known for his work in constructive complex analysis and numerical linear algebra. He supervised 17 PhD

dissertations and several of his students went on to academic positions. His students and colleagues remember him as a competent,

generous, helpful and always kind person. He served the mathematical community in many other ways, e.g., he was chair of the

Department of Mathematics in Karlsruhe, he served as “Fachgutachter” for applied mathematics on behalf of the Deutsche

Forschungsgemeinschaft (DFG) and led the DFG advisory board responsible for mathematics in the 1990’s. In addition he was on the

editorial board of various mathematical journals and, together with Richard S. Varga, organised several conferences at the Oberwolfach

Research Institute for Mathematics. Having been an enthusiastic mountain hiker (he mastered the Kilimanjaro in his late 50’s), these

conferences were famous for their hikes, starting with a steepest ascent right from the conference center.

Wilhelm Niethammer is survived by this wife and his two children, his daughter Barbara Niethammer being herself a well-known professor

for Applied Analysis at the Hausdorff Center for Mathematics in Bonn.

Michael Eiermann, Martin Hanke, Marlis Hochbruck, and Gerhard Starke