Steiner Tree Approximation via Iterative Randomized Rounding

Prize-Collecting Steiner Networks via Iterative Rounding

In this paper we design an iterative rounding approach for the classic prize-collecting Steiner forest problem and more generally the prize-collecting survivable Steiner network design problem. We show as an structural result that in each iteration of our algorithm there is an LP variable in a basic feasible solution which is at least one-third-integral resulting a 3-approximation algorithm for...

Approximation algorithms via randomized rounding: a survey

Approximation algorithms provide a natural way to approach computationally hard problems. There are currently many known paradigms in this area, including greedy algorithms, primal-dual methods, methods based on mathematical programming (linear and semidefinite programming in particular), local improvement, and “low distortion” embeddings of general metric spaces into special families of metric...

Steiner Tree Approximation - June 15

In this lecture we will summarize our recent work on Steiner tree approximation together with J. Byrka, T. Rothvoß and L. Sanità. Part of the results appeared in “An Improved LP-based Approximation for Steiner Tree” (STOC’10), and some other results are contained in the journal version of the paper, currently under revision. We will not be very formal, and we will abuse notation. We apologize f...

Approximation Algorithms: LP Relaxation, Rounding, and Randomized Rounding Techniques

Bicriteria Network Design via Iterative Rounding

We study the edge-connectivity survivable network design problem with an additional linear budget constraint. We give a strongly polynomial time (3, 3)-approximation algorithm for this problem, by extending a linear programming based technique of iterative rounding. Previously, a (4, 4)-approximation algorithm for this problem was known. The running time of this previous algorithm is not strong...