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

# Articles tagged computational complexity

### Complexity Theory Problem Strikes Back

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

### Computing’s Search for Quantum Questions

Recent tests show that quantum computers made by D-Wave systems should solve some problems faster than ordinary computers. Researchers have begun to map out exactly which queries might benefit from these quantum machines.

### Landmark Algorithm Breaks 30-Year Impasse

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

### Theorists Draw Closer to Perfect Coloring

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

### A New Map Traces the Limits of Computation

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

### A Grand Vision for the Impossible

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

### Computer Scientists Take Road Less Traveled

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