Traces and trajectories: in memory of Edi Zehnder (November 10, 1940–November 22, 2024)

Edi Zehnder began as a physicist, then turned to analytical dynamics studying small denominators, and eventually became one of the founding figures of (global) symplectic geometry and topology.He was born in Leuggern, a Swiss village in the canton of Aargau, where the Aare River merges with the Rhine.His father decided that the best education for him would be in a convent, so he attended high school at the boarding school of the Benedictine convent Einsiedeln.The education focused on ancient languages (Greek and Latin), and the only way to leave the convent during the week was to play in a local football club, which Edi did with enthusiasm.It was also at Einsiedeln that Edi met Jeannette (he 18 and she 15 at the time), who came with her class for a visit to the convent and was very impressed by Edi's pencil drawings and the fact that he smoked a pipe against the rules.From then on, they were together for 66 years, until Jeannette died three months before Edi.Edi studied mathematics and physics from 1960 until 1965 at ETH Zürich.The curricula of these two disciplines were nearly identical at that time.Heinz Hopf was no longer accepting PhD students, so Edi became a PhD student in theoretical physics, working under the supervision of Res Jost.