This article deals with the two-stage stochastic model, which aims at explicitly taking into account uncertainty in optimization problems, that Kong and Schaefer have recently studied for the maximum weight matching problem [N. Kong, A.J. Schaefer, A factor 1/2 approximation algorithm for...

We analyze the approximation behaviour of some of the best-known polynomial time approximation algorithms for bin-packing under an approximation criterion, called differential ratio. This measure has originally been introduced by Ausiello, D'Atri and Protasi and more recently revisited, in a...

This paper deals with the problem of constructing directed trees of optimal weight and root with depth at most (||) (called − ). We first prove that the maximization and the minimization versions are equal-approximable under the that measures how the value of an approximate solution is placed...