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

A group of chemists from Manchester have successfully tied a series of microscopic knots using individual molecules for the first time, ushering in the advent of a form of nano-scale weaving which ...

BUFFALO, N.Y. — You may not have heard of knot theory. But take it from Bill Menasco, a knot theorist of 35 years: This field of mathematics, rich in aesthetic beauty and intellectual challenges, has ...