An anonymous reader writes: When a top-tier mathematician announced in August that he had proved one of the greatest problems in mathematics, the claim was trumpeted in the New York Times, Nature, Science and the Boston Globe. Six months later, no one has any idea whether the proof is correct. Worse, no one has been able to explain the central ideas of the proof. Worse still, hardly anyone is even trying to understand it anymore, with the possible exception of a mathematician or two in Japan. This theorem in limbo shows how although people often think of mathematics as a solitary pursuit, with a written proof as final product, it’s an unavoidably social activity, even for mathematicians who prefer to work alone. A theorem isn’t proven until the mathematical community is persuaded that it’s proven. And the written proof is just the first step.