Horst Knoerrer: a professor in many roles
Professor Horst Knörrer has retired in August last year, after three decades at the Department of Mathematics. As a researcher he has been active in diverse fields of mathematics and physics, as a lecturer he taught across departments. His first new role after retirement will now be on the theatre stage – as an embittered medical professor.
"To me, it is particularly important that my audience perceives the sub-areas of mathematics that are taught in separate lectures not as entities that exist independently of one another. Instead, the students should be enabled to draw cross-connections between the individual theories. [...] Also for students who learn mathematics 'only' as an 'auxiliary science' it is particularly important to recognize mathematics as one unit." So cited the daily newspaper Neue Zürcher Zeitung the mathematician Horst Knörrer when he was introduced as the newly appointed professor at ETH Zurich (NZZ, 6.4.1988, p. 54).
Knörrer has been full Professor in the Mathematics Department starting from October 1987, until his recent retirement in August 2018. And it seems fair to say that during his three decades at ETH he followed through the route of taking a broad view on mathematics and science, and to convey that view with passion and dedication to others.
Across fields …
In his own research, Knörrer was keeping an open mind for new challenges throughout his career in Zurich. "I enjoyed the liberty that I was given to change between fields," he says today. Starting with algebraic geometry – where the abstract techniques of algebra are used to solve geometrical problems – his primary research interest moved to spectral theory, first in one dimension, and then in two and three, with ever growing links to mathematical physics. Eventually he turned his main attention to problems in physics, in particular many-body problems in solid-state physics.
Knörrer made important contributions to each of these fields, together with both international collaborators and colleagues at ETH. His opus is documented in numerous journal articles as well as in books, not least a well-known textbook on algebraic curves that he has written together with Egbert Brieskorn and which is considered a 'classic'.
… and departments
True to his words spoken on starting his career at ETH, a strong focus of Knörrer’s activities was on his "audience": his students, both in the Department of Mathematics and those for whom mathematics is primarily a toolbox. His lectures in analysis were heard by generations of students in departments across ETH. And many of those who attended these lectures will have fond memories of Horst Knörrer as an inspiring teacher. The Association of Students at ETH (VSETH) honoured him twice with the "Golden Owl" an award for exceptional teaching, in 2005 and 2015. 2005 was the year the award had been introduced, and not only did he receive on that occasion a "Golden Owl", but also the "Golden Eccentric". The latter was an award – unfortunately discontinued since then – for 'originality'. Knörrer earned that recognition for his performance as an amateur actor in a play centred on the theme of momentum conservation. That piece, "Cats always fall on their feet", he performed at various conferences, and also during a lecture at ETH. Evidently, the students appreciated the show.
Performance for various audiences
Acting was and remains an important part of Knörrer’s life. Growing up in the German festival city of Bayreuth, he visited rehearsals when he was a boy and saw festival visitors flocking through the streets every year. An early seed may have been planted then – together with a distinct dislike for Wagner. Acting became a full-grown passion after he started, in the early 2000s, taking courses for amateurs offered by the famous Swiss stage school Scuola Teatro Dimitri. Regular performances in amateur theatres followed.
The parallels between giving lectures in an auditorium and acting on a stage cannot be denied, says Knörrer: "In both cases, it is about conveying excitement and wonder". And parallels might be deceptively close in his newest project. Starting from January 2019, he will be the sole actor in "van Helsing", a stage play – in German – by the Belgian author and dramaturge Stephan Teuwissen, which will premiere later this month in "keller62", a professional stage in Zurich. The director is the young theatre maker Stephanie Schmidt.
In the play, mathematics professor Horst Knörrer will take the role of medical professor Abraham van Helsing, the archenemy of Count Dracula, whom he eventually defeated. The play is not about those heroic days themselves, though. Instead, the audience encounters van Helsing decades on, grown bitter and cynical, ranting in a one-hour monologue about Dracula and the world, about science and academia, and about the lack of appreciation that he, van Helsing, has received for his deeds.
A special sort of farewell lecture then? "By no means," is Knörrer’s clear answer. "The play is about a fictional character, not about my life." Nonetheless, all members of the department, and of ETH, are warmly welcome to attend one of the eight performances currently scheduled. The opening night will be on 29 January 2019.