2015年04期 (共 篇) 引用文章 全选
+ 摘要浏览:34 全文浏览：1 全文下载：1
In the paper we introduce the notions of the separation factorκand give a representive of metric projection on an n-codimension subspace (or an a?ne set) under certain conditions in Banach space. Further, we obtain the distance formula from any point x to a finite n-codimension subspace. Results extend and improve the corresponding results in Hilbert space.
+ 摘要浏览:29 全文浏览：1 全文下载：0
We introduce, in this paper, the right weakly p.p. rings as the generaliza-tion of right p.p. rings. It is shown that many properties of the right p.p. rings can be extended onto the right weakly p.p. rings. Relative examples are constructed. As applications, we also characterize the regular rings and the semisimple rings in terms of the right weakly p.p. rings.
+ 摘要浏览:45 全文浏览：1 全文下载：0
We study numerical methods for level set like equations arising in im-age processing and curve evolution problems. Semi-implicit finite volume-element type schemes are constructed for the general level set like equation (image selective smoothing model) given by Alvarez et al. (Alvarez L, Lions P L, Morel J M. Image selective smoothing and edge detection by nonlinear diffusion II. SIAM J. Numer. Anal., 1992, 29: 845–866). Through the reasonable semi-implicit discretization in time and co-volume method for space approximation, we give finite volume schemes, unconditionally stable in L∞ and W 1,2 (W 1,1) sense in isotropic (anisotropic) diffu-sion domain.
+ 摘要浏览:31 全文浏览：6 全文下载：3
In this paper, we discuss a kind of Hermitian inner product—symplectic inner product, which is different from the original inner product — Euclidean inner product. According to the definition of symplectic inner product, the codes under the symplectic inner product have better properties than those under the general Hermitian inner product. Here we present the necessary and su?cient condition for judging whether a linear code C over Fp with a generator matrix in the standard form is a symplectic self-dual code. In addition, we give a method for constructing a new symplectic self-dual codes over Fp, which is simpler than others.
+ 摘要浏览:22 全文浏览：0 全文下载：1
In this paper, we study the characteristic properties for Lp-centroid bod-ies, and an improved version of Busemann-Petty problem for Lp-centroid bodies is obtained. In addition, using the definitions of Lp-pole curvature image and Lp-a?ne surface area, a new proof of Busemann-Petty problem for Lp-centroid bodies is given.
+ 摘要浏览:29 全文浏览：0 全文下载：0
In this paper, a biquartic finite volume element method based on Lobatto-Guass structure is presented for variable coe?cient elliptic equation on rectangular partition. Not only the optimal H1 and L2 error estimates but also some super-convergent properties are available and could be proved for this method. The numer-ical results obtained by this finite volume element scheme confirm the validity of the theoretical analysis and the effectiveness of this method.
+ 摘要浏览:32 全文浏览：7 全文下载：3
Let G be a generalized matrix algebra over a commutative ring R and Z(G) be the center of G. Suppose that F, T:G?→G are two co-commuting R-linear mappings, i.e., F (x)x=xT (x) for all x∈G. In this note, we study the question of when co-commuting mappings on G are proper.
+ 摘要浏览:36 全文浏览：0 全文下载：1
In this paper, a predator-prey system with two discrete delays and stage structure for both the predator and the prey is investigated. The dynamical be-haviors such as local stability and local Hopf bifurcation are analyzed by regarding the possible combinations of the two delays as bifurcating parameter. Some explicit formulae determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form method and the center manifold theory. Finally, numerical simulations are presented to support the theoretical analysis.
Boundedness of Commutators Generated by Campanato-typ e Functions and Riesz Transforms Asso ciated with Schr¨odinger Op erators
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Let L = ??+V be a Schr¨odinger operator on Rn, n > 3, where ?is the Laplacian on Rn and V = 0 is a nonnegative function satisfying the reverse H¨olders inequality. Let [b, T ] be the commutator generated by the Campanato-type function b∈ΛβL and the Riesz transform associated with Schr¨odinger operator T =?(??+V )?12 . In the paper, we establish the boundedness of [b, T ] on Lebesgue spaces and Campanato-type spaces.