For more than a decade Facebook, now known as Meta, has awarded fellowships to promising graduate students working on cutting-edge research. The prize, which this year comes with up to two years’ worth of university tuition and a $42,000 stipend, has gone to computer scientists, engineers, physicists and statisticians. Now it has gone to an economist. “I was not expecting it,” says Jaume Vives i Bastida, the lucky recipient working on a…