Two mathematicians have proved that a straightforward question—how hard is it to untie a knot?—has a complicated answer.

Christoph Thiele and Floris van Doorn from the University of Bonn have been awarded an ERC Synergy Grant of 6.4 million euros ...

With more than a decade of experience, Nelson covers Apple and Google and writes about iPhone and Android features, privacy and security settings, and more. As the holidays approach, millions of ...