Public debates about classification by algorithms has created tension around what it means to be fair to different groups. As part of Northwestern Engineering's Dean's Seminar Series on May 13, Cornell University’s Jon Kleinberg discussed key fairness conditions at the heart of these debates, and recent work on the interactions between these conditions. He also explored how the complexity of a classification rule interacts with its fairness properties, showing how natural ways of approximating a classifier via a simpler rule can act in conflict with fairness goals.