共查询到20条相似文献,搜索用时 31 毫秒
1.
Miroslav Chlebík 《Discrete Applied Mathematics》2006,154(14):1960-1965
In this paper we prove that the PRECOLORING EXTENSION problem on graphs of maximum degree 3 is polynomially solvable, but even its restricted version with 3 colors is NP-complete on planar bipartite graphs of maximum degree 4.The restricted version of LIST COLORING, in which the union of all lists consists of 3 colors, is shown to be NP-complete on planar 3-regular bipartite graphs. 相似文献
2.
The general strategy of impossible differential cryptanalysis is to first find impossible differentials and then exploit them for retrieving subkey material from the outer rounds of block ciphers. Thus, impossible differentials are one of the crucial factors to see how much the underlying block ciphers are resistant to impossible differential cryptanalysis. In this article, we introduce a widely applicable matrix method to find impossible differentials of block cipher structures whose round functions are bijective. Using this method, we find various impossible differentials of known block cipher structures: Nyberg’s generalized Feistel network, a generalized CAST256-like structure, a generalized MARS-like structure, a generalized RC6-like structure, Rijndael structures and generalized Skipjack-like structures. We expect that the matrix method developed in this article will be useful for evaluating the security of block ciphers against impossible differential cryptanalysis, especially when one tries to design a block cipher with a secure structure. 相似文献
3.
J. Sugie 《Acta Mathematica Hungarica》2008,118(4):369-394
This paper deals with the second-order half-linear differential equation
Here ϕ
p
(z):= |z|
p−2
z is the so-called one-dimensional p-Laplacian operator. Our main purpose is to establish new criteria for all nontrivial solutions to be oscillatory and for
those to be nonoscillatory. In our theorems, the parametric curve given by (a(t), b(t)) plays a critical role in judging whether all solutions are oscillatory or nonoscillatory. This paper takes a di-erent approach
from most of the previous research. Our results are new even in the linear case (p = 2). The method used here is mainly phase plane analysis for a system equivalent to the half-linear differential equation.
Some suitable examples are included to illustrate the main results. Global phase portraits are also attached.
Supported in part by Grant-in-Aid for Scientific Research 19540182. 相似文献
4.
Rainer Buckdahn 《Probability Theory and Related Fields》1992,93(3):297-323
Leta, b beC
2(R
1)-functions with bounded derivatives of first and second order. We study stochastic differential equations
相似文献
5.
M. Guedda 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2005,56(5):749-762
This paper is concerned with the ordinary differential equation
6.
O. V. Zakharova 《Russian Mathematics (Iz VUZ)》2009,53(6):1-6
In this paper we prove that instead of solving a class of systems of stochastic differential equations with a multidimensional Wiener process one can solve a system of total differential equations. The latter system admits an application of classical methods. This fact enables one to solve the initial system explicitly. 相似文献
7.
K. Mørken 《Constructive Approximation》1991,7(1):195-208
In this paper it is shown how the algebraic product of two spline functions, each represented in terms of B-splines, can again be represented as a linear combination of suitable B-splines. As a corollary to this result we obtain an explicit representation of a given B-spline function in terms of B-splines of some arbitrary higher degree. This generalizes some known results for raising the degree by one. Recurrence relations for both products and degree raising are established that may be useful for computation.Communicated by Larry L. Schumaker. 相似文献
8.
We study systems with delay effect that contain additional algebraic relations. We propose semiexplicit numerical methods of the Rosenbrock type. We prove the solvability of equations of a numerical model and estimate the order of the global error. The chosen parameters provide the third order of the error. 相似文献
9.
It is proved that the even-order equationy
(2n)
+p(t)y=0 is (n,n) oscillatory at if
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