共查询到20条相似文献,搜索用时 31 毫秒
1.
本文讨论如下抛物型Monge-Ampere方程的第一初边值问题-ut+det1/n D2u=g(χ,t),(χ,t)∈Q=Ω×(0,T),u= (χ,t),(χ,t)∈ pQ,其中Ω为Rn中有界凸集.证明了在更一般的结构条件下[3,7]的结果仍然成立.证明中重要的一点是在Rn × R中非柱型域上“冻结问题”的可解性. 相似文献
2.
This is a continuation of our investigation of classes of sequences of positive real numbers satisfying some selection principles as well as having certain game-theoretic properties. We improve main results from [D. Djur?i?, Lj.D.R. Ko?inac, M.R. ?i?ovi?, Some properties of rapidly varying sequences, J. Math. Anal. Appl. 327 (2007) 1297-1306] and [D. Djur?i?, Lj.D.R. Ko?inac, M.R. ?i?ovi?, Rapidly varying sequences and rapid convergence, Topology Appl. (2008), doi: 10.1016/j.topol.2007.05.026, in press]. 相似文献
3.
This paper is devoted to asymptotically absorbing operator nets. The study of such nets has attracted an attention in [19, 20] in connection with the notion of the Lotz ?? R?biger nets on a Banach space which had been studied recently in [4, 8, 9, 18?C20]. In the present paper, we focus mainly on the case of nets of positive linear operators. 相似文献
4.
1984年,Ho Kuen Ng在[1]中给出了交换环与模的有限表现维数(简称为F.P.—维数)的定义及若干有意义的重要结果.从此,有限表现性的讨论成为环论的热门课题之一.作者在[2]中将有限表现维数推广到非交换环上.并利用有限表现维数刻划了凝聚环,在[3]中讨论了有限表现维数的换环定理.在[4]中讨论了笛卡尔方形上的有限表现维数.丁南庆在[5]中推广了有限表现维数,给出了一种新维数——模的有限生成维数,在[6]中讨论了有限表现模的对偶 相似文献
5.
Jun Ji 《计算数学(英文版)》1989,7(4):327-333
Algebraic perturbation methods were first proposed for the solution of nonsingular linear systems by R. E. Lynch and T. J. Aird [2]. Since then, the algebraic perturbation methods for generalized inverses have been discussed by many scholars [3]-[6]. In [4], a singular square matrix was perturbed algebraically to obtain a nonsingular matrix, resulting in the algebraic perturbation method for the Moore-Penrose generalized inverse. In [5], some results on the relations between nonsingular perturbations and generalized inverses of $m\times n$ matrices were obtained, which generalized the results in [4]. For the Drazin generalized inverse, the author has derived an algebraic perturbation method in [6]. In this paper, we will discuss the algebraic perturbation method for generalized inverses with prescribed range and null space, which generalizes the results in [5] and [6]. We remark that the algebraic perturbation methods for generalized inverses are quite useful. The applications can be found in [5] and [8]. In this paper, we use the same terms and notations as in [1]. 相似文献
6.
Fernando Hernández-Hernández Paul J. Szeptycki Artur H. Tomita 《Topology and its Applications》2007,154(16):2997-3004
We study realcompactness in the classes of submaximal and maximal spaces. It is shown that a normal submaximal space of cardinality less than the first measurable is realcompact. ZFC examples of submaximal not realcompact and maximal not realcompact spaces are constructed. These examples answer questions posed in [O.T. Alas, M. Sanchis, M.G. Tka?enko, V.V. Tkachuk, R.G. Wilson, Irresolvable and submaximal spaces: homogeneity versus σ-discreteness and new ZFC examples, Topology Appl. 107 (3) (2000) 259-273] and generalize some results from [D.P. Baturov, On perfectly normal dense subspaces of products, Topology Appl. 154 (2) (2007) 374-383]. 相似文献
7.
Anne Fearnley 《Algebra Universalis》2007,56(2):165-177
We describe the clones on 3 elements that can be expressed as Pol ρ for ρ a binary relation. We present the poset of these
clones ordered by inclusion. This article is a shortened version of the author’s thesis, to give an idea of the whole work.
Presented by R. P?schel.
Received March 24, 2005; accepted in final form December 20, 2005. 相似文献
8.
V. Nesi 《NoDEA : Nonlinear Differential Equations and Applications》1997,4(2):283-303
We establish lower bounds for the overall conductivity of a class of non linear composites. The composites are made of an
arbitrary number of anisotropic phases. The local 'density of energy' is subquadratic. This problem cannot be treated by most
methods considered in the existing literature such as the well known generalization of the linear Hashin-Shtrikman method
due to Willis [33] and developed by Talbot & Willis [30]. Very recently, Talbot and Willis have developed a new method based
on certain properties of BMO functions [31], [32]. Their calculations apply when the phases are isotropic. However when at
least one of the phases is not isotropic, the only result available, prior to the present work, was the classical Wiener bound.
We develop yet another method which is completely different from that of Talbot and Willis. It is based on the idea of using
an appropriate reverse Holder inequality. The main mathematical tools come from the theory of planar quasiconformal mappings.
We use results due to Astala [1] and Eremenko and Hamilton [11]. Our new bounds apply, under certain hypotheses, to two dimensional
problems. When they apply they are always at least as good as those of Wiener. We exhibit examples in which our bounds are
strictly better.
Received October 29, 1995 相似文献
9.
《Expositiones Mathematicae》2001,19(3):213-227
We show how to compute a geometrical presentation for a finitely generated fuchsian group G from the explicit knowledge of a fundamental polygon for G. We use a previous work on fat-graphs [4]. In particular, our result is a complement to the works of R.S. Kulkarni [10] and S. Johansson [5] on arithmetic fuchsian groups. 相似文献
10.
11.
The binary [24,12,8] Golay code has projection O onto the quaternary [6,3,4] hexacode [9] and the [32,16,8] Reed-Muller code
has projection E onto the quaternary self-dual [8,4,4] code [6]. Projection E was extended to projection G in [8]. In this
paper we introduce a projection, to be called projection Λ, that covers projections O, E and G. We characterise G-projectable
self-dual codes and Λ-projectable codes. Explicit methods for constructing codes having G and Λ projections are given and
several so constructed codes that have best known optimal parameters are introduced.
相似文献
12.
Olivier Esser 《Mathematical Logic Quarterly》1996,42(1):104-108
M. Forti and F. Honsell showed in [4] that the hyperuniverses defined in [2] satisfy the anti-foundation axiom X1 introduced in [3]. So it is interesting to study the axiom AFA, which is equivalent to X1 in ZF, introduced by P. Aczel in [1]. We show in this paper that AFA is inconsistent with the theory GPK. This theory, which is first order, is defined by E. Weydert in [6] and later by M. Forti and R. Hinnion in [2]. It includes all general hyperuniverses as defined in [5]. In order to achieve our aim, we need to define ordinals in GPK and to study some of their properties. Mathematics Subject Classification: 03E70, 03E10. 相似文献
13.
Let D [d] =(a,b/F) a quaternion divisior algebra over a field F of characteristic ? 2. Denote 1, i, j , k the basis of D, such that i2[d] n, j2[d] b, ij [d] -ji [d] k and A :D → D the involution given by i [d] -i, j [d] j (and k [d] k). In [LE] D. LEWIS asks the following question :Does there exist a quadratic Pfister form [S p. 721 [d] such that the hermitian form [d] [d] D is isotropic over (D, [d]) but not hyperbolic &; In this note, we show that the answer of this question is negative, so that the hermitien level [§I], when it is finite, of (D, A) is a power of two. This result holds for quaternion algebras with standard involution [LE]. 相似文献
14.
Frank Eckstein 《代数通讯》2013,41(5):365-376
Simple locally compact rings without open left ideals were considered in [13] and general locally compact rings without open left ideals were studied extensively in [5] and [6]. We remove the hypothesis of local compactness and consider topological rings A without open left ideals but containing an open subring R. In section 4 we show that under these conditions A is completely determined by R. More precisely A can be identified with the topological ring of quotients C(R) introduced in [8]. As an R-module RA is topologically isomorphic to I*(RR), the topological injective hull of RR. The last statement was proved in [6] for A locally compact and R compact. Section 5 gives a characterization of those linearly topologized rings R that can be openly embedded into a ring A without open left ideals. In particular we shall show that the open left ideals form an idempotent ideal filter with quotient ring A. In section 6 we consider the class ? of all topological rings that can be openly embedded into a topological ring without open left ideals. If we restrict our attention to linearly topologized rings, then ? is Morita-invariant. In section 2 we construct a topological ring of quotients Q*(R) and prove that it coincides with the ring C(R) of [8]. 相似文献
15.
Susan Tolman 《Inventiones Mathematicae》1998,131(2):299-310
An important question with a rich history is the extent to which the symplectic category is larger than the K?hler category.
Many interesting examples of non-K?hler symplectic manifolds have been constructed [T] [M] [G]. However, sufficiently large
symmetries can force a symplectic manifolds to be K?hler [D] [Kn]. In this paper, we solve several outstanding problems by
constructing the first symplectic manifold with large non-trivial symmetries which does not admit an invariant K?hler structure.
The proof that it is not K?hler is based on the Atiyah-Guillemin-Sternberg convexity theorem [At] [GS]. Using the ideas of
this paper, C. Woodward shows that even the symplectic analogue of spherical varieties need not be K?hler [W].
Oblatum IX-1995 & 3-III-1997 相似文献
16.
Laurent Fargues 《Comptes Rendus Mathematique》2002,334(9):739-742
In this Note we announce results concerning the first part of a programme intending to generalize the articles [5,7] and thus construct local Langlands correspondences for groups other than GLn (for example, quasisplit unitary groups) inside the ? adic cohomology of Rapoport–Zink spaces. The method consists in comparing the cohomology of these local objects with that of global objects: Shimura varieties. For this we generalize the spectral sequences constructed in [5] and [4]. A part of these results is quoted in [6]. To cite this article: L. Fargues, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 739–742. 相似文献
17.
The aim of this paper is to prove the existence and uniqueness of local solutions of some initial boundary value problems for the Euler equations of an incompressible fluid in a bounded domain Ω ? R 2 with corners. We consider two cases of a nonvanishing normal component of velocity on the boundary. In three-dimensional case such problems have been considered in papers [12], [13], [14]. Similar problems in domains without corners have been considered in [2]–[6], [11]. In this paper the relation between the maximal corner angle of the boundary and the smoothness of the solutions is shown. The paper consists of four sections. In section 1 two initial boundary value problems for the Euler equations are formulated. In section 2 the existence and uniqueness of solutions of the Laplace equation in twodimensional domain with corners for the Dirichlet and Neumann problems is proved in the Sobolev spaces. In sections 3 and 4 we prove the existence and uniqueness of solutions of problems formulated in section 1, using the method of successive approximations. 相似文献
18.
We generalize three approaches on graph transformations, respectively, from Stevanovi? and Ili? (2009) [16] and Tan (2011) [19]. We also generalize an approach of graph transformations on the spectral radius of adjacency matrix into the Laplacian coefficients of graphs from Li and Feng (1979) [26]. Moreover, we determine the unique tree having the third maximal Laplacian coefficients among all n-vertex trees. 相似文献
19.
本文讨论拟微分算子象证的Witt乘积与C[x]▲△A.G[p]的乘积之间的关系,得到以下结果:具有Witt乘积的象证类S1.0^m。是具有普通乘积的函数类S1.0^m经过对Hopf代数的乘积量子化得到的,进一步,给出了C[x]▲△h.cC[p]上标准的辫导数的显示表示,并且证明了其上的Poisson括号与经典的具有同一形式. 相似文献
20.
G-集分次模与Morita Context 总被引:5,自引:1,他引:5
对任意群G, H≤G,[1]研究了G-分次环R与有限可迁G-集的smash积.在本文中我们对任意可迁G-集,讨论了一个关于R(H)与smash积R#G/H的Morita context,从而推广了[2],[3],[4]给出的关于G-分次环及其与群G的smash积的一些重要结果. 相似文献