Carl Ludwig Siegel

Carl Ludwig Siegel (December 31, 1896 – April 4, 1981) was a mathematician specialising in number theory and celestial mechanics. He was one of the most important mathematicians of the 20th century. Siegel was born in Berlin, where he enrolled at the Humboldt University in Berlin in 1915 as a student in mathematics, astronomy, and physics. Amongst his teachers were Max Planck and Ferdinand Georg Frobenius, whose influence made the young Siegel abandon astronomy and turn towards number theory instead. His best student was Jürgen Moser, one of the founders of KAM theory (Kolmogorov-Arnold-Moser), which lies at the foundations of chaos theory. In 1917 Siegel was drafted into the German Army. Since he refused military service, he was...