## Jeremy Kahn

Jeremy Kahn knew he had friends at Brown University.

In the summer of 1992, Kahn was visiting a scientific institute in France when his path crossed with another mathematician, Richard Schwartz. “I walk up to this guy, and I say, *‘Parlez-vous anglais?’* and he started to describe his work. We talked all summer and stayed close friends.”

Some years later, Schwartz joined the math faculty at Brown. Along with Brown math professor Jeffrey Brock, whom Kahn knew from graduate studies at the University of California–Berkeley, it’s fair to say that the 41-year-old Kahn will feel at home as incoming professor of mathematics.

He plans to make even more connections once he arrives this fall. Besides Schwartz and Brock, Kahn is excited to trade ideas on combinatorial geometry with fellow professors Hee Oh and Richard Kenyon. “It’s a great group,” Kahn said, after ticking off the names. “So, for me, it’s a fantastic place to work.”

A major research pursuit is hyperbolic geometry. It’s much like Euclidian geometry, or plane geometry, with one important difference. Whereas in Euclidean geometry parallel lines maintain a constant distance from each other and thus never intersect, “The whole idea of hyperbolic geometry is they don’t stay at a constant distance from each other,” Kahn said. “The lines remain straight, but the space where the lines are is curved.”

Studying Riemann surfaces is another area of interest. A Riemann surface is a surface-like configuration that covers the complex plane with several — often infinitely many — “sheets,” which can have very complicated structures and interconnections. He will teach a graduate-level class on Riemann geometry this fall and is expected to teach a course this spring at the new NSF-funded Institute for Computational and Experimental Research in Mathematics at Brown.

Kahn grew up on the upper West Side in New York City. He graduated from Harvard with a degree in mathematics and earned his doctorate at Berkeley. He has been an assistant professor at the California Institute of Technology and at Stony Brook University, as well as a postdoctoral fellow at the University of Toronto. After about a decade in academia, Kahn decided to take a splash in the “real world,” as he called it, taking a job as an analyst with the investment management firm Highbridge Capital Management. His task was to use math to divine the movement of stocks.

“I enjoyed working with the people in the group, but I didn’t like what we were doing,” he said.

He stuck with it for a year, then returned to academia. “I wanted to at least try to apply my mind to a real-life problem,” he said. “What I really want to do is think and spend my time thinking about really hard problems. But it would be nice if the problems were engaged in the real world.”

Kahn plans to live in Providence. In his free time, he can be found cooking, biking, taking walks on the beach or reacquainting himself with snow skiing. He may even turn on the SciFi channel — a mathematician with an interest in “Battlestar Galactica.”