Results 281 to 290 of about 504,784 (313)

Covering Numbers in Covering-Based Rough Sets

2011
Rough set theory provides a systematic way for rule extraction, attribute reduction and knowledge classification in information systems. Some measurements are important in rough sets. For example, information entropy, knowledge dependency are useful in attribute reduction algorithms.
Shiping Wang, Fan Min 0001, William Zhu 0001   +2 more
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Set Cover at Web Scale

Proceedings of the 21th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, 2015
The classic Set Cover problem requires selecting a minimum size subset A ⊆ F from a family of finite subsets F Of U such that the elements covered by A are the ones covered by F. It naturally occurs in many settings in web search, web mining and web advertising.
Stergios Stergiou, Kostas Tsioutsiouliklis   +1 more
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Minimal covering sets for infinite set systems

Discrete Mathematics, 2019
Given a set \(V\) and a collection \(\mathcal H\) of non-empty subsets of \(V\), \(M \subseteq V\) is a covering set if \(M \cap A \neq \emptyset\) for all \(A \in \mathcal H\). \(M\) is a minimal covering set if \(M\) is a covering set and no proper subset of \(M\) is a covering set.
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Covering Properties of Convex Sets

Bulletin of the London Mathematical Society, 1986
Partant d'un recouvrement ouvert de certains convexes d'un espace vectoriel topologique séparé, l'A. obtient un recouvrement fermé contenu dans le premier. Le caractère fermé du recouvrement lui permet alors d'utiliser un résultat classique afin d'obtenir une démonstration élégante d'un résultat récent de Ky Fan.
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A theorem on the approximation of set cover and vertex cover

1991
An approximation result is given, connecting two well known combinatorial problems, the Set Cover and the Vertex Cover. This result constitutes an improvement of the existing ratio for the latter, on a large and intuitive class of graphs, provided that an approximation algorithm exists for the former.
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Covering the edges with consecutive sets

Journal of Graph Theory, 1991
AbstractThe following question is answered in this note: for which graphs G can the vertices of G be linearly ordered so that all the minimal vertex covers of G are consecutive sets?.
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The Set Cover with Pairs Problem

2005
We consider a generalization of the set cover problem, in which elements are covered by pairs of objects, and we are required to find a minimum cost subset of objects that induces a collection of pairs covering all elements. Formally, let U be a ground set of elements and let ${\cal S}$ be a set of objects, where each object i has a non-negative cost ...
Refael Hassin, Danny Segev
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COVERINGS OF PAIRS BY k-SETS

Annals of the New York Academy of Sciences, 1970
Stanton, R. G., Kalbfleisch, J. G.
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Pairs Covered by a Sequence of Sets

2015
Enumerating minimal new combinations of elements in a sequence of sets is interesting, e.g., for novelty detection in a stream of texts. The sets are the bags of words occuring in the texts. We focus on new pairs of elements as they are abundant. By simple data structures we can enumerate them in quadratic time, in the size of the sets, but large ...
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Covering problems in facility location: A review

Computers and Industrial Engineering, 2012
Reza Zanjirani Farahani, Nasrin Asgari, Mark Goh   +2 more
exaly