Erica Klarreich

Contributing Correspondent

symmetry

How to Make Impossible Wallpaper

March 5, 2013

A new collection of arresting wallpaper designs seems to defy the crystallographic restriction.

traveling salesperson problem

Computer Scientists Take Road Less Traveled

January 29, 2013

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

cryptography

Privacy by the Numbers: A New Approach to Safeguarding Data

December 10, 2012

A mathematical technique called “differential privacy” gives researchers access to vast repositories of personal data while meeting a high standard for privacy protection.

Mathematics

Getting Into Shapes: From Hyperbolic Geometry to Cube Complexes and Back

October 2, 2012

Thirty years after William Thurston articulated a grand mathematical vision, a proof by Ian Agol marks the end of an era in the study of three-dimensional shapes.