How to find the best approximation results

A compendium of NP optimization problems, containing the best approximation results known for each problem, is available on the world wide web at http://www.nada.kth.se/~viggo/problemlist/In this paper we describe the compendium, and specify how the compendium is consultable as well as modifiable on the web. We also give statistics for the use of the compendium.