Approximation, randomization, and combinatorial optimization algorithms and techniques : 9th International Workshop on Approximation Algorithms for Combinatorial Optimization Problems, APPROX 2006 and 10th International Workshop on Randomization and Computation, RANDOM 2006, Barcelona, Spain, August 28-30, 2006 : proceedings - Diaz, Josep; Jansen, Klaus; Rolim, José D. P.; Zwick, Uri (Lecture Notes in Computer Science, 2006)