What's up in

The theoretical computer scientist behind the influential Unique Games Conjecture delights in the wonders of New York’s Washington Square Park, where he ponders the impossible.

Asexual reproduction can produce twice as many offspring as sexual reproduction without the hassle of finding and courting a mate. So why do most complex animals have two sexes? Why not three?

Big advances in math can happen when mathematicians move ideas into areas where they seem like they shouldn’t belong.

June Huh thought he had no talent for math until a chance meeting with a legendary mind. A decade later, his unorthodox approach to mathematical thinking has led to major breakthroughs.

An obscure number theorist who became an overnight sensation with a major proof about the gaps between prime numbers now finds quiet inspiration walking along the Pacific Coast.

Paul Erdős placed small bounties on hundreds of unsolved math problems. Over the past 20 years, only a handful have been claimed.

The three young friends who devised the “happy ending” problem would become some of the most influential mathematicians of the 20th century, but were never able to solve their own puzzle. Now it receives its first big breakthrough.

Juggling has advanced enormously in recent decades, thanks in part to the mathematical study of possible patterns.

There’s more than one good way to bring order to our unruly, seemingly arbitrary calendar.