منابع مشابه
Covering Numbers in Covering-Based Rough Sets
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. This paper proposes the concepts of the lower and upper covering numbers to establish measurements in covering-b...
متن کاملNew Covering Array Numbers
A covering array CA(N ; t, k, v) is anN×k array on v symbols such that everyN×t subarray contains as a row each t-tuple over the v symbols at least once. The minimum N for which a CA(N ; t, k, v) exists is called the covering array number of t, k, and v, and it is denoted by CAN(t, k, v). In this work we prove that if exists CA(N ; t+ 1, k + 1, v) it can be obtained from the juxtaposition of v ...
متن کاملOn Covering Numbers
A positive integer n is called a covering number if there are some distinct divisors n1, . . . , nk of n greater than one and some integers a1, . . . , ak such that Z is the union of the residue classes a1(mod n1), . . . , ak(mod nk). A covering number is said to be primitive if none of its proper divisors is a covering number. In this paper we give some sufficient conditions for n to be a (pri...
متن کاملAdditivity Numbers of Covering Properties
The additivity number of a topological property (relative to a given space) is the minimal number of subspaces with this property whose union does not have the property. The most well-known case is where this number is greater than א0, i.e. the property is σ-additive. We give a rather complete survey of the known results about the additivity numbers of a variety of topological covering properti...
متن کاملCovering Numbers in Linear Algebra
We compute the minimal cardinalities of coverings and irredundant coverings of a vector space over an arbitrary field by proper linear subspaces. Analogues for affine linear subspaces are also given. Notation: The cardinality of a set S will be denoted by #S. For a vector space V over a field K , we denote its dimension by dim K . 1. LINEAR COVERINGS. Let V be a vector space over a field K . A ...
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ژورنال
عنوان ژورنال: Journal of Combinatorial Designs
سال: 2015
ISSN: 1063-8539
DOI: 10.1002/jcd.21425