Google Engineer, Long Out of Math, Cracks Devilish Problem About Sets

In mid-October, Justin Gilmer flew from California to New York to attend a friend’s wedding. While on the East Coast he visited his former adviser, Michael Saks, a mathematician at Rutgers University, where Gilmer had received his doctorate seven years earlier. Saks and Gilmer caught up over lunch, but they didn’t talk about math. In fact, Gilmer had not thought seriously about math since…

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