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51.
Sans résumé
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52.
Runge–Kutta based convolution quadrature methods for abstract, well-posed, linear, and homogeneous Volterra equations, non
necessarily of sectorial type, are developed. A general representation of the numerical solution in terms of the continuous
one is given. The error and stability analysis is based on this representation, which, for the particular case of the backward
Euler method, also shows that the numerical solution inherits some interesting qualitative properties, such as positivity,
of the exact solution. Numerical illustrations are provided. 相似文献
53.
杨青 《高校应用数学学报(A辑)》2002,17(3):353-362
热传导型半导体器件的瞬时状态由四个方程的非线性偏微分方程组的初边值问题所决定,其中电子位势方程是椭圆型的,电子和空穴浓度方程是对流扩散型的,温度方程为热传导型的。本文提出解这类问题的特征变网格有限元法,并进行了理论分析,在一定条件下,得到了某种意义下的最佳L^2误差估计结果。 相似文献
54.
为了更好地理解和应用样本分位数的极限分布,利用Slutsky定理,推导了样本分位数的极限分布. 相似文献
55.
In this paper, we establish a theorem on the distribution of primes in quadratic progressions on average. 相似文献
56.
以陆地棉(冀棉20)下胚轴为外植体,在含KT0.3mg/L和2,4-D0.08mg/L的MS培养基上,诱导产生了胚性愈伤组织,继代培养不需要添加激素,胚性愈伤组织即分化为胚状体,并萌发出小芽,胚状体萌发过程与合子胚相似,但出现了一些畸形胚,解剖学方法观察发现,这些畸形胚的维管束系统不明显或形态异常,以农杆菌介导法对冀棉20胚状体及胚性愈伤组织进行了雪花莲凝集素(GNA)基因的遗传转化条件探索,并以GUS基域瞬间进行检测加以证实,得出农杆菌的浓度为O.D600=0.8时,浸染时间为5min,共培养时间为3d,筛选培养基中卡那霉素浓度为75mg/L,对冀棉20胚状体及胚性愈伤组织转化是较为适合的。 相似文献
57.
Bosco García-Archilla 《Numerische Mathematik》1992,61(1):291-310
Summary A finite-difference method for the integration of the Korteweg-de Vries equation on irregular grids is analyzed. Under periodic boundary conditions, the method is shown to be supraconvergent in the sense that, though being inconsistent, it is second order convergent. However, such a convergence only takes place on grids with an odd number of points per period. When a grid with an even number of points is used, the inconsistency of the method leads to divergence. Numerical results backing the analysis are presented. 相似文献
58.
In this paper we define and study an extension of the g-Drazin for elements of a Banach algebra and for bounded linear operators based on an isolated spectral set rather than on
an isolated spectral point. We investigate salient properties of the new inverse and its continuity, and illustrate its usefulness
with an application to differential equations. Generalized Mbekhta subspaces are introduced and the corresponding extended
Mbekhta decomposition gives a characterization of circularly isolated spectral sets. 相似文献
59.
Jon Wilkening 《Linear algebra and its applications》2007,427(1):6-25
We present an efficient algorithm for obtaining a canonical system of Jordan chains for an n × n regular analytic matrix function A(λ) that is singular at the origin. For any analytic vector function b(λ), we show that each term in the Laurent expansion of A(λ)−1b(λ) may be obtained from the previous terms by solving an (n + d) × (n+d) linear system, where d is the order of the zero of det A(λ) at λ = 0. The matrix representing this linear system contains A(0) as a principal submatrix, which can be useful if A(0) is sparse. The last several iterations can be eliminated if left Jordan chains are computed in addition to right Jordan chains. The performance of the algorithm in floating point and exact (rational) arithmetic is reported for several test cases. The method is shown to be forward stable in floating point arithmetic. 相似文献
60.
LetC(X,E) andC(Y,F) denote the spaces of continuous functions on the Tihonov spacesX andY, taking values in the Banach spacesE andF, respectively. A linear mapH:C(X,E)→C(Y,F) isseparating iff(x)g(x)=0 for allx inX impliesHf(y)Hg(y)=0 for ally inY. Some automatic continuity properties and Banach-Stone type theorems (i.e., asserting that isometries must be of a certain
form) for separating mapsH between spaces of real- and complex-valued functions have already been developed. The extension of such results to spaces
of vector-valued functions is the general subject of this paper. We prove in Theorem 4.1, for example, for compactX andY, that a linear isometryH betweenC(X,E) andC(Y,F) is a “Banach-Stone” map if and only ifH is “biseparating (i.e,H andH
−1 are separating). The Banach-Stone theorems of Jerison and Lau for vector-valued functions are then deduced in Corollaries
4.3 and 4.4 for the cases whenE andF or their topological duals, respectively, are strictly convex.
Research supported by the Fundació Caixa Castelló, MI/25.043/92 相似文献