共查询到10条相似文献,搜索用时 62 毫秒
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Michael G. Neubauer William Watkins Joel Zeitlin 《Linear algebra and its applications》1998,280(2-3):109-127
The purpose of this paper is to exhibit new infinite families of D-optimal (0, 1)-matrices. We show that Hadamard designs lead to D-optimal matrices of size (j, mj) and (j − 1, mj), for certain integers j ≡ 3 (mod 4) and all positive integers m. For j a power of a prime and j ≡ 1 (mod 4), supplementary difference sets lead to D-optimal matrices of size (j, 2mj) and (j − 1, 2mj), for all positive integers m. We also show that for a given j and d sufficiently large, about half of the entries in each column of a D-optimal matrix are ones. This leads to a new relationship between D-optimality for (0, 1)-matrices and for (±1)-matrices. Known results about D-optimal (±1)-matrices are then used to obtain new D-optimal (0, 1)-matrices. 相似文献
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Let m ? 7 be an integer and let M m ,7 (0,1) be the set of all m × 7 (0,1)-matrices. Define $$ G(m,7) = \max \{ \det X^T X|X \in M_{m,7} (0,1)\} . \eqno (1) $$ A matrix X for which the maximum is achieved is said to be D- optimal . We determine G ( m , 7) for sufficiently large m and exhibit D-optimal matrices. For each m , the Gram matrices, X T X for D-optimal matrices X ε M m ,7 (0,1), are shown to be essentially unique. 相似文献
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《Quaestiones Mathematicae》2013,36(3):279-291
ABSTRACT In the general setting of a complete, well-powered category A, we define and study two universal closure operations: regularization and extremalization, by means of regular and extremal subobjects of A. respectively. A general theorem of characterization of epimorphisms in A is given. When A is an epireflective subcategory of TOP, such operations are shown to coincide with A-closure [11] and epiclosure [2]. respectively. In the topological contest, regularization and extremalization are studied in detail and compared with r-closure, defined in [13]. 相似文献
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Li Huishi 《数学年刊B辑(英文版)》1994,15(4):463-468
It is proved that for a left Noetherian z-graded ring A,if every finitely generated graded A-module has finite projective dimension(i.e-,A is gr-regular)then every finitely generated A-module has finite projective dimension(i.e.,A is regular).Some applications of this result to filtered rings and some classical cases are also given. 相似文献
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LI HUISHI 《数学年刊B辑(英文版)》1994,(4)
NOETHERIANGT-REGULARRINGSAREREGULAR¥LIHUISHI(DepartmentofMathematics,ShaanxiNormalUnivisityXi'an710062,China.)Abstract:Itispr... 相似文献
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1引言 设A=(a_η)∈Cm~(3n),若存在正对角阵D.使得AD为严格对角占优矩阵,则A称为广义严格对角占优矩阵,记作A∈SGDDM. 相似文献
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《高等学校计算数学学报(英文版)》2000,(Z1)
It is known that nearly uncoupled irreducible stochastic matrices must possess sub-dominant eigenvalues near λ=1. It is nature to ask whether the converse is true. Hortfieland Meyer [2] gave a positive answer. They introduced the notion of uncoupling measureof Stochastic matrices. For an n×n stochastic matrix P the uncoupling measure of P is de-fined as σ(p)=min((sum from i∈M_1,j∈M_1(P_(ij)))+(sum from i∈M_1,j∈M_1(P_(ij))), where the minimum is taken over all 相似文献