David Bessis received his PhD in pure mathematics from University Paris-Cité. After a career at Yale University, CNRS, and École normale supérieure (with research topics in algebra, geometry, and topology), his interests shifted from pure mathematics to machine learning, leading him to establish a technology company in this field. He lives in Paris, France. Kevin Frey received a PhD in English from the State University of New York at Stony Brook. He lives in Kaneohe, HI.