منابع مشابه
Hard Capacitated Set Cover and Uncapacitated Geometric Set Cover
The first part of this report describes the following result that, logarithmic approximation factor for hard capacitated set cover can be achieved from Wolsey's work [9], using a simpler and more intuitive analysis. We further show in our work, that O(log n) approximation factor can be achieved for the same problem by applying analysis of general set cover to analyze Wolsey's algorithm [5]. Thi...
متن کاملSet Cover Revisited: Hypergraph Cover with Hard Capacities
In this paper, we consider generalizations of classical covering problems to handle hard capacities. In the hard capacitated set cover problem, additionally each set has a covering capacity which we are not allowed to exceed. In other words, after picking a set, we may cover at most a specified number of elements. Based on the classical results by Wolsey, an O(log n) approximation follows for t...
متن کاملA Characterization of Hard-to-cover CSPs
We continue the study of covering complexity of constraint satisfaction problems (CSPs) initiated by Guruswami, Håstad and Sudan [9] and Dinur and Kol [7]. The covering number of a CSP instance Φ, denoted by ν(Φ) is the smallest number of assignments to the variables of Φ, such that each constraint of Φ is satisfied by at least one of the assignments. We show the following results regarding how...
متن کاملIterative Partial Rounding for Vertex Cover with Hard Capacities
We provide a simple and novel algorithmic design technique, for which we call itera-tive partial rounding, that gives a tight rounding-based approximation for vertex cover withhard capacities (VC-HC). In particular, we obtain an f -approximation for VC-HC on hy-pergraphs, improving over a previous results of Cheung et al (SODA 2014) to the tightextent. This also closes the g...
متن کاملSimple lifted cover inequalities and hard knapsack problems
We consider a class of random knapsack instances described by Chvátal, who showed that with probability going to 1, such instances require an exponential number of branch-and-bound nodes. We show that even with the use of simple lifted cover inequalities, an exponential number of nodes is required with probability going to 1. It is not surprising that there exist integer programming (IP) instan...
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ژورنال
عنوان ژورنال: Gadjah Mada International Journal of Business
سال: 2014
ISSN: 2338-7238,1411-1128
DOI: 10.22146/gamaijb.5664