2026 Sue Geller Undergraduate Lecture 

 Abstract:  Each day your actions generate data, and that data is being used at some cost to your privacy. "Differentially private" algorithms seek to protect the privacy of individual data, often by injecting some randomness. Such mechanisms have been used by Apple, Google, Uber, and the US Census Bureau. I'll describe how such algorithms work and discuss recent efforts to quantify how much randomness is needed to guarantee privacy but still give accurate answers. Surprisingly, this analysis involves the geometry of sets positioned in space in clever ways.

 Bio of Francis Su:    Francis Su is the Benediktsson-Karwa Professor of Mathematics at Harvey Mudd College, a former president of the Mathematical Association of America, and a Fellow of the American Mathematical Society. In 2013, he received the Haimo Award, a nationwide teaching prize for college math faculty, and in 2018 he won the Halmos-Ford writing award. His research is in geometric combinatorics and applications to the social sciences, he has published many papers with undergraduates. His work has been featured in Quanta Magazine, Wired, and the New York Times. His book Mathematics for Human Flourishing (2020), winner of the 2021 Euler Book Prize, has been translated into 8 languages. It offers an inclusive vision of what math is, who it's for, and why anyone should learn it.