Is there an infinity of infinities? The question sounds almost absurd, like a child’s riddle meant to twist your brain into ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

One of the strangest results in mathematics explains how it’s possible to turn one sphere into two identical copies, simply by rearranging its pieces. Imagine two friends hiking in the woods. They ...