Approximation algorithms for facility location problems (extended abstract)
STOC '97 Proceedings of the twenty-ninth annual ACM symposium on Theory of computing
A threshold of ln n for approximating set cover
Journal of the ACM (JACM)
Greedy strikes back: improved facility location algorithms
Journal of Algorithms
Greedy strikes back: improved facility location algorithms
Proceedings of the ninth annual ACM-SIAM symposium on Discrete algorithms
A 3-approximation algorithm for the k-level uncapacitated facility location problem
Information Processing Letters
Polynomially Solvable Cases of the Simple Plant Location Problem
Proceedings of the 1st Integer Programming and Combinatorial Optimization Conference
An Improved Approximation Algorithm for the Metric Uncapacitated Facility Location Problem
Proceedings of the 9th International IPCO Conference on Integer Programming and Combinatorial Optimization
Improved Approximation Algorithms for Metric Facility Location Problems
APPROX '02 Proceedings of the 5th International Workshop on Approximation Algorithms for Combinatorial Optimization
A Simple Dual Ascent Algorithm for the Multilevel Facility Location Problem
APPROX '01/RANDOM '01 Proceedings of the 4th International Workshop on Approximation Algorithms for Combinatorial Optimization Problems and 5th International Workshop on Randomization and Approximation Techniques in Computer Science: Approximation, Randomization and Combinatorial Optimization
Greedy facility location algorithms analyzed using dual fitting with factor-revealing LP
Journal of the ACM (JACM)
Improved Approximation Algorithms for the Uncapacitated Facility Location Problem
SIAM Journal on Computing
Improved Combinatorial Approximation Algorithms for the k-Level Facility Location Problem
SIAM Journal on Discrete Mathematics
Improved Combinatorial Algorithms for Facility Location Problems
SIAM Journal on Computing
Approximating the two-level facility location problem via a quasi-greedy approach
Mathematical Programming: Series A and B
Facility location with hierarchical facility costs
ACM Transactions on Algorithms (TALG)
A new approximation algorithm for the multilevel facility location problem
Discrete Applied Mathematics
Approximation algorithms for combinatorial problems
Journal of Computer and System Sciences
An Optimal Bifactor Approximation Algorithm for the Metric Uncapacitated Facility Location Problem
SIAM Journal on Computing
Improved approximation algorithms for multilevel facility location problems
Operations Research Letters
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In this paper, we present improved inapproximability results for the k-level uncapacitated facility location problem. In particular, we show that there is no polynomial time approximation algorithm with performance guarantee better than 1.539 unless NP is contained in DTIME(nO(log log n)) for the case when k = 2. For the case of general k (tendining to infinity) we obtain a better hardness factor of 1.61. Interestingly, our results show that the two-level problem is computationally harder than the well known uncapacitated facility location problem (k = 1) since the best known approximation guarantee for the latter problem is 1.488 due to Li [22], and our inapproximability is a factor of 1.539 for the two-level problem. The only inapproximability result known before for this class of metric facility location problems is the bound of 1.463 due to Guha and Khuller [17], which holds even for the case of k = 1.