Computational complexity

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.

Just five days after posting a retraction, László Babai announced that he had fixed the error in his landmark graph isomorphism algorithm.

The legendary graph isomorphism problem may be harder than a 2015 result seemed to suggest.

Computer scientists are abuzz over a fast new algorithm for solving one of the central problems in the field.

A theorem for coloring a large class of “perfect” mathematical networks could ease the way for a long-sought general coloring proof.

A major advance in computational complexity reveals deep connections between the classes of problems that computers can — and can’t — possibly do.

Subhash Khot’s bold conjecture is helping mathematicians explore the precise limits of computation.

An infinitesimal advance in the traveling salesman problem breathes new life into the search for improved approximate solutions.