Computational complexity

By chopping up large numbers into smaller ones, researchers have rewritten a fundamental mathematical speed limit.

These games combine quantum entanglement, infinity and impossible-to-calculate winning probabilities. But if researchers can crack them, they’ll reveal deep mathematical secrets.

18-year-old Ewin Tang has proven that classical computers can solve the “recommendation problem” nearly as fast as quantum computers. The result eliminates one of the best examples of quantum speedup.

What’s easy for a computer to do, and what’s almost impossible? Those questions form the core of computational complexity. We present a map of the landscape.

Computer scientists have been searching for years for a type of problem that a quantum computer can solve but that any possible future classical computer cannot. Now they’ve found one.

The latest in a new series of proofs brings theoretical computer scientists within striking distance of one of the great conjectures of their discipline.

The real-world version of the famous “traveling salesman problem” finally gets a good-enough solution.

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.