共查询到20条相似文献,搜索用时 9 毫秒
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可补为可逆2×2分块算子缺项矩阵 总被引:1,自引:0,他引:1
本文给出了缺项算子矩阵可补为可逆算子矩阵,且它的逆矩阵的一块等于已知矩阵的条件,同时给出了问题解的一般形式,对可补为可逆自共轭算子的问题也进行了一些讨论. 相似文献
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本文提出了分块矩阵弱相似的概念,探讨了分块矩阵弱相似的条件和性质,得到了若干有意义的结果,为解决有关实际问题提供了一定的理论依据。 相似文献
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In the present paper we prove a Korovkin type approximation theorem for a sequence of positive linear operators acting from
a weighted space Cρ1 into a weighted space Bρ2 with the use of a matrix summability method which includes both convergence and almost convergence. We also study the rates
of convergence of these operators. 相似文献
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Cichon Dariusz; Stochel Jan; Szafraniec Franciszek H. 《Journal London Mathematical Society》2006,73(3):762-782
Criteria for selfadjointness of integral operators, includingmatrix operators, based on our earlier domination results areestablished. The range of applicability is elucidated by carefullychosen examples, not covered by previously known criteria. 相似文献
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求分块三对角矩阵和分块周期三对角矩阵逆矩阵的快速算法 总被引:1,自引:0,他引:1
给出了分块三对角矩阵逆矩阵的快速算法,并利用所给算法得到了求分块周期三对角矩阵逆矩阵的快速算法.最后通过算例表示算法的有效性. 相似文献
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石油资源已频临日益枯竭的境地,因而对内燃机代用燃料的研究广泛廾展,植物油做为柴油机代用燃料的研究已遍布世界各国,本文主要介绍国内外植物油燃料的试验研究情况,植物油与其他代用燃料的比较,以及对发展我国植物油燃料的研究谈一些看法,提出一些具体建议。 相似文献
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F. Weisz 《Acta Mathematica Hungarica》1998,80(3):249-264
The atomic decomposition of weak Hardy spaces consisting of Vilenkin martingales is formulated. Some sufficient conditions for a sublinear operator T to be bounded from the weak Hardy space wHp to the weak wLp space are given. As applications a weak version of the Hardy-Littlewood inequality is obtained and it is shown that the maximal operator of the Cesàro means of a Vilenkin-Fourier series is bounded from wHp to wLp and is of weak type (1, 1). This yields that the Cesàro means of a function f L1 converge a.e. to the function in question, provided that the Vilenkin system is bounded. 相似文献
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We propose a new family of matrix models whose 1/N expansion captures the all-genus topological string on toric Calabi–Yau threefolds. These matrix models are constructed from the trace class operators appearing in the quantization of the corresponding mirror curves. The fact that they provide a non-perturbative realization of the (standard) topological string follows from a recent conjecture connecting the spectral properties of these operators, to the enumerative invariants of the underlying Calabi–Yau threefolds. We study in detail the resulting matrix models for some simple geometries, like local \({\mathbb{P}^2}\) and local \({\mathbb{F}_2}\), and we verify that their weak ’t Hooft coupling expansion reproduces the topological string free energies near the conifold singularity. These matrix models are formally similar to those appearing in the Fermi-gas formulation of Chern–Simons matter theories, and their 1/N expansion receives non-perturbative corrections determined by the Nekrasov–Shatashvili limit of the refined topological string. 相似文献
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In this article the scattering matrix pertaining to the defocusing matrix Zakharov-Shabat system on the line is related to
the scattering operator arising from time-dependent scattering theory. Further, the scattering data allowing for a unique
retrieval of the potential in the defocusing matrix Zakharov-Shabat system are characterized.
The research leading to this article was supported in part by the Italian Ministery of Education
and Research (MIUR) under PRIN grant no. 2006017542-003, and by INdAM. One of the authors
(CvdM) wishes to express his gratitude for the hospitality of the Department of Mathematics of
the University of Texas at Arlington during the Spring Semester of 2008 when part of the paper
was written. 相似文献
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Operator Matrix Forms of Positive Operators 总被引:2,自引:0,他引:2
If a 3-tuple (A:H1→H1,B:H2→H1,C:H2→H2)of operators on Hibert spaces is given,we proved that the operator ~↑A:=(↑A ↓B^*↑B ↓C) on H=H1 H2 is ≥0 is and only if A≥0,R(B)∪→R(A^1/2) and C≥B^* A^ b,where A^ is the generalized inverse of A.In general,A^ is a closed operator,but since R(B)∪→R(A^1/2,B^* A^ B is bounded yet. 相似文献
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Suppose that d≥1 is an integer, α∈(0,d) is a fixed parameter and let I α be the fractional integral operator associated with d-dimensional Walsh-Fourier series on (0,1] d . Let p, q be arbitrary numbers satisfying the conditions 1≤p<d/α and 1/q=1/p?α/d. We determine the optimal constant K, which depends on α, d and p, such that for any f∈L p ((0,1] d ) we have In fact, we shall prove this inequality in the more general context of probability spaces equipped with a regular tree-like structures. This allows us to obtain this result also for non-integer dimension. The proof exploits a certain modification of the so-called Bellman function method and appropriate interpolation-type arguments. We also present a sharp weighted weak-type bound for I α , which can be regarded as a version of the Muckenhoupt-Wheeden conjecture for fractional integral operators.
相似文献
$$ ||I_{\alpha } f||_{L^{q,\infty }((0,1]^{d})}\leq K||f||_{L^{p}((0,1]^{d})}. $$
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We consider one class of matrix differential operators in the whole space. For this class of operators we establish the isomorphic properties in some special scales of weighted Sobolev spaces and study the regularity properties for solutions to the system of differential equations defined by these operators. The class of operators under consideration contains the stationary Navier–Stokes operator. 相似文献