Mathematicians have long pondered the reach of a grazing goat tied to a fence, only finding approximate answers until now. Here’s a simple-sounding problem: Imagine a circular fence that encloses one ...

There is a tendency to imagine genius as smooth and uninterrupted. As if the great thinkers moved from one insight to the next without pause. Albert Einstein does not quite fit that picture. For all ...

One idle evening last October, Mehtaab Sawhney took up an old pastime. He began perusing the website erdosproblems.com, an updated record of the 1,179 conjectures left behind by the eccentric and ...