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931.
932.
递推数列x_(n+1)=f(x_n)的单调性与收敛性讨论 总被引:1,自引:0,他引:1
利用函数单调递增对递推数列xn+1=f(xn)单调性进行讨论,在对递推数列收敛性作分析的基础上,得到使得递推数列收敛的初始迭代值的区域,讨论的方法可以用于类似问题的研究. 相似文献
933.
Henrik Petersson 《Journal of Approximation Theory》2006,138(2):168-183
A sequence of continuous linear operators is said to be hypercyclic if there exists a vector , called hypercyclic for , such that {Tnx:n0} is dense. A continuous linear operator, acting on some suitable function space, is PDE-preserving for a given set of convolution operators, when it map every kernel set for these operators invariantly. We establish hypercyclic sequences of PDE-preserving operators on , and study closed infinite-dimensional subspaces of, except for zero, hypercyclic vectors for these sequences. 相似文献
934.
For a signed graph G and function , a signed f‐factor of G is a spanning subgraph F such that sdegF(υ) = f(υ) for every vertex υ of G, where sdeg(υ) is the number of positive edges incident with v less the number of negative edges incident with υ, with loops counting twice in either case. For a given vertex‐function f, we provide necessary and sufficient conditions for a signed graph G to have a signed f‐factor. As a consequence of this result, an Erd?s‐Gallai‐type result is given for a sequence of integers to be the degree sequence of a signed r‐graph, the graph with at most r positive and r negative edges between a given pair of distinct vertices. We discuss how the theory can be altered when mixed edges (i.e., edges with one positive and one negative end) are allowed, and how it applies to bidirected graphs. © 2006 Wiley Periodicals, Inc. J Graph Theory 52: 27–36, 2006 相似文献
935.
Wenming Zou 《Journal of Functional Analysis》2006,234(2):364-419
Some parameter-depending linking theorems are established, which allow to produce a bounded and sign-changing Palais-Smale sequence. For even functionals, a parameter-depending fountain theorem is obtained which provides infinitely many bounded and sign-changing Palais-Smale sequences. A variant mountain pass theorem is built in cones which yields bounded, positive and negative Palais-Smale sequences. The usual Palais-Smale type compactness condition and its variants are completely not necessary for these theories. More exact locations of the critical sequences can be determined. The abstract results are applied to the Schrödinger equation with (or without) critical Sobolev exponents:
936.
In this paper, we introduce the notion of bounded Betti numbers, and show that the bounded Betti numbers of a closed Riemannian n-manifold (M, g) with Ric (M) ≥ -(n - 1) and Diam (M) ≤ D are bounded by a number depending on D and n. We also show that there are only finitely many isometric isomorphism types of bounded cohomology groups (H*(M), || · ||∞) among closed Riemannian manifold (M, g) with K(M) ≥-1 and Diam (M) ≤ D. 相似文献
937.
** Email: zhengjhluck{at}hotmail.com In this paper, we consider the optimal attitude maneuver designfor a non-linear flexible spacecraft with vibrating solar arrays.Two different linearization methods for the non-linear systemare compared in this study. One is the recursive approximatingsequence approach (RASA) to design a time-varying linear quadraticregulator (LQR) for the non-linear system and the other is todesign a LQR by linearizing the non-linear system at each locallyfrozen state in any sufficient small sphere alongthe trajectory. Numerical simulation shows that the later approachgives good design results quickly by scanning the time axisonly one time. The RASA method may scan the time axis severaltimes to get a good approach. Moreover, both linearization methodsgive satisfying control results in attitude maneuver and vibrationsuppression control for the non-linear flexible spacecraft. 相似文献
938.
Yusuf Civan 《Proceedings of the American Mathematical Society》2006,134(5):1537-1548
We study the enumeration problem of stably complex structures on bounded flag manifolds arising from omniorientations, and determine those induced by almost complex structures. We also enumerate the stably complex structures on these manifolds which bound, therefore representing zero in the complex cobordism ring .
939.
It is a classical result of Bernstein that the sequence of Lagrange interpolation polynomials to |x| at equally spaced nodes in [-1, 1] diverges everywhere, except at zero and the end-points. In the present paper, we prove that the sequence of Lagrange interpolation polynomials corresponding to |x|α(2 <α< 4) on equidistant nodes in [-1,1] diverges everywhere, except at zero and the end-points. 相似文献
940.
In this paper we have proved a main theorem concerning the | $\bar N$ , p n; δ |k summability methods, which generalizes a result of Bor and Özarslan [3]. 相似文献