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

# Articles tagged mathematics

### How Many Half-Lives Do You Have?

Gaining an intuition about half-life requires some unintuitive thinking.

### How Curvature Makes a Shape a Shape

The ancient study of an object’s curvature is guiding mathematicians toward a new understanding of simple equations.

### Complexity Theory Problem Strikes Back

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

### Test Your Mathematical Sculpting Skills

Can you turn a two-dimensional fractal into a 3-D object? Break out your scissors and tape for a chance to win a 3-D printed sculpture.

### 3-D Fractals Offer Clues to Complex Systems

By folding fractals into 3-D objects, a mathematical duo hopes to gain new insight into simple equations.

### Solution: ‘Hanging Far Out Over the Edge’

A simple and elegant way to stack identical flat objects so that they project over an edge as far as possible.

### The Math That’s Too Difficult for Physics

How do physicists reconstruct what really happened in a particle collision? Through calculations that are so challenging that, in some cases, they simply can’t be done. Yet.

### How to Hang Far Out Over the Edge

What formula describes the farthest you can stack flat blocks over the edge of a table to form a seemingly gravity-defying half-bridge to nowhere?

### Strange Numbers Found in Particle Collisions

An unexpected connection has emerged between the results of physics experiments and an important, seemingly unrelated set of numbers in pure mathematics.