共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
Toma? Kosem 《Linear algebra and its applications》2006,418(1):153-160
The conjecture posed by Aujla and Silva [J.S. Aujla, F.C. Silva, Weak majorization inequalities and convex functions, Linear Algebra Appl. 369 (2003) 217-233] is proved. It is shown that for any m-tuple of positive-semidefinite n × n complex matrices Aj and for any non-negative convex function f on [0, ∞) with f(0) = 0 the inequality ?f(A1) + f(A2) + ? + f(Am)? ? ? f(A1 + A2 + ? + Am)? holds for any unitarily invariant norm ? · ?. It is also proved that ?f(A1) + f(A2) + ? + f(Am)? ? f(?A1 + A2 + ? + Am?), where f is a non-negative concave function on [0, ∞) and ? · ? is normalized. 相似文献
3.
Houria Triki 《Applied mathematics and computation》2010,217(4):1733-9479
We consider the nonlinear dispersive K(m,n) equation with the generalized evolution term and derive analytical expressions for some conserved quantities. By using a solitary wave ansatz in the form of sechp function, we obtain exact bright soliton solutions for (2 + 1)-dimensional and (3 + 1)-dimensional K(m,n) equations with the generalized evolution terms. The results are then generalized to multi-dimensional K(m,n) equations in the presence of the generalized evolution term. An extended form of the K(m,n) equation with perturbation term is investigated. Exact bright soliton solution for the proposed K(m,n) equation having higher-order nonlinear term is determined. The physical parameters in the soliton solutions are obtained as function of the dependent model coefficients. 相似文献
4.
本文研究了环Fpm+uFpm+u2Fpm上长度为ps的循环码分类.通过建立环Fpm+uFpm+u2Fpm到环Fpm+uFpm的同态,给出了环Fpm+uFpm+u2Fpm上长度为ps的循环码的新分类方法.应用这种方法,得到了环Fpm+uFpm+u2Fpm长度为ps的循环码的码词数. 相似文献
5.
Vladimir Umanskiy 《Advances in Mathematics》2003,180(1):176-186
Given p≠0 and a positive continuous function g, with g(x+T)=g(x), for some 0<T<1 and all real x, it is shown that for suitable choice of a constant C>0 the functional has a minimizer in the class of positive functions u∈C1(R) for which u(x+T)=u(x) for all x∈R. This minimizer is used to prove the existence of a positive periodic solution y∈C2(R) of two-dimensional Lp-Minkowski problem y1−p(x)(y″(x)+y(x))=g(x), where p∉{0,2}. 相似文献
6.
Special exact solutions of the K(2, 2) equation, ut + (u2)x + (u2)xxx = 0, are investigated by employing the qualitative theory of differential equations. Our procedure shows that the K(2, 2) equation either has loop soliton, cusped soliton and smooth soliton solutions when sitting on the non-zero constant pedestal limx→±∞u = A ≠ 0, or possesses compacton solutions only when limx→±∞u = 0. Mathematical analysis and numerical simulations are provided for these soliton solutions of the K(2, 2) equation. 相似文献
7.
Jianfa Qian Lina Zhang Shixin Zhu 《Journal of Applied Mathematics and Computing》2006,22(1-2):159-167
The transform domain characterization of cyclic codes over finite fields using Discrete Fourier Transform(DFT) over an appropriate extension field is well known. In this paper, we extend this transform domain characterization for cyclic codes overF p +uF p + ··· +u k-1 F p . We give a way to characterize cyclic codes overF p +uF p + ··· +u k-1 F p by Mattson-Solomon polynomials and multiple defining sets. 相似文献
8.
This paper develops a gradient based and a least squares based iterative algorithms for solving matrix equation AXB + CXTD = F. The basic idea is to decompose the matrix equation (system) under consideration into two subsystems by applying the hierarchical identification principle and to derive the iterative algorithms by extending the iterative methods for solving Ax = b and AXB = F. The analysis shows that when the matrix equation has a unique solution (under the sense of least squares), the iterative solution converges to the exact solution for any initial values. A numerical example verifies the proposed theorems. 相似文献
9.
Antoine Brunel 《Comptes Rendus Mathematique》2002,334(3):205-207
We consider positive linear operators on Lp-spaces (1<p<∞), (A(Lp+)?Lp+), satisfying the inequality Am+n<Am+An for all We describe the structure of these operators (Theorem 1). As a consequence we obtain for all f∈Lp,Anf converges a.e. The last statement contains the theorem of a.e. convergence of Cesaro averages for positive mean bounded operators. To cite this article: A. Brunel, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 205–207. 相似文献
10.
11.
Jing Cai 《Applied mathematics and computation》2010,217(1):117-4466
Nonlinear matrix equation Xs + A∗X−tA = Q, where A, Q are n × n complex matrices with Q Hermitian positive definite, has widely applied background. In this paper, we consider the Hermitian positive definite solutions of this matrix equation with two cases: s ? 1, 0 < t ? 1 and 0 < s ? 1, t ? 1. We derive necessary conditions and sufficient conditions for the existence of Hermitian positive definite solutions for the matrix equation and obtain some properties of the solutions. We also propose iterative methods for obtaining the extremal Hermitian positive definite solution of the matrix equation. Finally, we give some numerical examples to show the efficiency of the proposed iterative methods. 相似文献
12.
In this paper, the nonlinear matrix equation X + A∗XqA = Q (q > 0) is investigated. Some necessary and sufficient conditions for existence of Hermitian positive definite solutions of the nonlinear matrix equations are derived. An effective iterative method to obtain the positive definite solution is presented. Some numerical results are given to illustrate the effectiveness of the iterative methods. 相似文献
13.
Yuan-Wei QiMing-Xing Wang 《Journal of Mathematical Analysis and Applications》2002,267(1):264-280
In this paper we study the critical exponents of the Cauchy problem in Rn of the quasilinear singular parabolic equations: ut = div(|∇u|m − 1∇u) + ts|x|σup, with non-negative initial data. Here s ≥ 0, (n − 1)/(n + 1) < m < 1, p > 1 and σ > n(1 − m) − (1 + m + 2s). We prove that pc ≡ m + (1 + m + 2s + σ)/n > 1 is the critical exponent. That is, if 1 < p ≤ pc then every non-trivial solution blows up in finite time, but for p > pc, a small positive global solution exists. 相似文献
14.
We study some structural aspects of the subspaces of the non-commutative (Haagerup) Lp-spaces associated with a general (non-necessarily semi-finite) von Neumann algebra . If a subspace X of contains uniformly the spaces ?pn, n?1, it contains an almost isometric, almost 1-complemented copy of ?p. If X contains uniformly the finite dimensional Schatten classes Spn, it contains their ?p-direct sum too. We obtain a version of the classical Kadec-Pe?czyński dichotomy theorem for Lp-spaces, p?2. We also give operator space versions of these results. The proofs are based on previous structural results on the ultrapowers of , together with a careful analysis of the elements of an ultrapower which are disjoint from the subspace . These techniques permit to recover a recent result of N. Randrianantoanina concerning a subsequence splitting lemma for the general non-commutative Lp spaces. Various notions of p-equiintegrability are studied (one of which is equivalent to Randrianantoanina's one) and some results obtained by Haagerup, Rosenthal and Sukochev for Lp-spaces based on finite von Neumann algebras concerning subspaces of containing ?p are extended to the general case. 相似文献
15.
Humio Ichimura 《Journal of Number Theory》2002,96(1):105-132
Let p be an odd prime number, K an imaginary abelian field with ζp∈K×, and K∞/K the cyclotomic Zp-extension with its nth layer Kn. In the previous paper, we showed that for any n and any unramified cyclic extension L/Kn of degree p, LKn+1/Kn+1 does have a normal integral basis (NIB) even if L/Kn has no NIB, under the assumption that p does not divide the class number of the maximal real subfield K+ (and some additional assumptions on K). In this paper, we show that similar but more delicate phenomena occur for a certain class of tamely ramified extensions of degree p. 相似文献
16.
Yabo Chen 《Applied mathematics and computation》2010,217(1):230-236
A new matrix based iterative method is presented to compute common symmetric solution or common symmetric least-squares solution of the pair of matrix equations AXB = E and CXD = F. By this iterative method, for any initial matrix X0, a solution X∗ can be obtained within finite iteration steps if exact arithmetic was used, and the solution X∗ with the minimum Frobenius norm can be obtained by choosing a special kind of initial matrix. In addition, the unique nearest common symmetric solution or common symmetric least-squares solution to given matrix in Frobenius norm can be obtained by first finding the minimum Frobenius norm common symmetric solution or common symmetric least-squares solution of the new pair of matrix equations. The given numerical examples show that the matrix based iterative method proposed in this paper has faster convergence than the iterative methods proposed in [1] and [2] to solve the same problems. 相似文献
17.
Figen Öke 《Applied mathematics and computation》2011,218(3):956-958
Let v be a valuation of a field K, Gv its value group and kv its residue field. Let w be an extension of v to K(x1, … , xn). w is called a residual transcendental extension of v if kw/kv is a transcendental extension. In this study a residual transcendental extension w of v to K(x1, … , xn) such that transdegkw/kv = n is defined and some considerations related with this valuation are given. 相似文献
18.
19.
Using the concepts of conditional expectation and independence of subalgebras, we characterize those contractive projections, P, on Lp, over a probability measure space, having the property that I − P is contractive. By contractive projection we mean a linear operator, P, on the Lebesgue space, Lp, 1 < p < ∞, ≠2, with P2 = P, ∥ = 1. 相似文献
20.
We obtain structural results about group ring codes over F[G], where F is a finite field of characteristic p > 0 and the Sylow p-subgroup of the Abelian group G is cyclic. As a special case, we characterize cyclic codes over finite fields in the case the length of the code is divisible
by the characteristic of the field. By the same approach we study cyclic codes of length m over the ring R = F
q
[u], u
r
= 0 with r > 0, gcd(m, q) = 1. Finally, we give a construction of quasi-cyclic codes over finite fields.
相似文献