Mostnaturaloptimizationproblems,includingthosearisinginimportant applicationareas,areNP-hard.Therefore,underthewidelybelievedconjecture thatP-=/=NP,theirexactsolutionisprohibitivelytimeconsuming. Chartingthelandscapeofapproximabilityoftheseproblems,viapolynomial t