lems get harder very fast as the number of elements goes up. A 50-city problem is hugely larger than a five-city problem, not just ten times harder. The Clay Mathematics Institute has offered a $1 million prize for anyone who can say whether NP problems are really as hard as they appear. It may be there is a general trick or a

from first principles that confinement is indeed a mathematical property of quantum chromodynamics? This is the million-dollar question, literally. The Clay Mathematics Institute has announced a million-dollar prize for a rigorous mathematical proof that quantum chromodynamics does not allow free quarks or gluons to be prod