Two mathematicians have proved that a straightforward question—how hard is it to untie a knot?—has a complicated answer.
2don MSN
String theory: Scientists are trying new ways to verify the idea that could unite all of physics
In 1980, Stephen Hawking gave his first lecture as Lucasian Professor at the University of Cambridge. The lecture was called ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results
Feedback