共查询到20条相似文献,搜索用时 15 毫秒
1.
Tomas Schonbek 《Journal of Differential Equations》1985,56(2):290-296
New and more elementary proofs are given of two results due to W. Littman: (1) Let . The estimate cannot hold for all u?C0∞(Q), Q a cube in , some constant C. (2) Let n ? 2, p ≠ 2. The estimate cannot hold for all C∞ solutions of the wave equation □u = 0 in ; all t ?; some function C: → . 相似文献
2.
F. Götze 《Journal of multivariate analysis》1981,11(2):260-272
Let P(Θ, τ) 6 , θ ∈ Θ ? , τ ∈ T ? p denote a family of probability measures, where τ denotes the vector of nuisance parameters. Starting from randomized asymptotic maximum likelihood (as. m. l.) estimators for (θ, τ) we construct randomized estimators which are asymptotically median unbiased up to resp. test procedures which are as. similar of level (for testing θ = θ0, τ ∈ T against one sided alternatives). The estimation procedures are second-order efficient in the class of estimators which are median unbiased up to and the test procedures are second-order efficient in the class of tests which are as. of level . These results hold without any continuity condition on the family of probability measures. 相似文献
3.
For a given pair such that A is cyclic and b is a cyclic generator (with respect to A) of , it is shown that for every nonnegative integer m we can find a nonnegative integer t and a sequence ,so that a the zeros of the rational function det P(z), where f, lie in the open unit disc in the complex plane. The result is directly applicable to a stabilizability problem for linear systems with a time delay in control action. 相似文献
4.
This paper deals with asymptotic behavior for (weak) solutions of the equation , on + × Ω; u(t, x) = 0, on + × ?Ω. If and β is coercive, we prove that the solutions are bounded in the energy space, under weaker assumptions than those used by G. Prouse in a previous work. If in addition and ? is srongly almost-periodic, we prove for strongly monotone β that all solutions are asymptotically almost-periodic in the energy space. The assumptions made on β are much less restrictive than those made by G. Prouse: mainly, we allow β to be multivalued, and in the one-dimensional case β need not be defined everywhere. 相似文献
5.
Minoru Murata 《Journal of Functional Analysis》1984,56(3):300-310
Let H = ?Δ + V, where V is a multiplication operator by a real-valued function V(x) on Rn which is uniformly Hölder continuous and for some ? > 4. The relationship between existence of positive solutions, with growth conditions, of Hg = 0 and asymptotic behaviors as t → ∞ of e?th is established. Using it B. Simon's problem for H on R2 is solved. 相似文献
6.
D Gaier 《Journal of Mathematical Analysis and Applications》1979,70(1):236-239
Let ? be defined on Tr and have an absolutely convergent Fourier series . Set . In this paper the problem of determining the limit of , as n → ∞, is studied. 相似文献
7.
F.R.K Chung 《Journal of Combinatorial Theory, Series A》1984,36(3):342-354
A classical problem in combinatorial geometry is that of determining the minimum number f(n) of different distances determined by n points in the Euclidean plane. In 1952, L. Moser proved that and this has remained for 30 years as the best lower bound known for f(n). It is shown that for some fixed constant c. 相似文献
8.
Detlef Wille 《Discrete Mathematics》1974,10(1):189-192
A formula for the number am(2n) of self-complementary m-placed relations is given. Then we obtain from this formula asymptotic results, e.g. 相似文献
9.
According to a result of A. Ghizzetti, for any solution y(t) of the differential equation where , (0 ?i ? n ?1, either y(t) = 0 for t ? 1 or there is an integer r with 0 ? r ? n ? 1 such that exists and ≠0. Related results are obtained for difference and differential inequalities. A special case of the former has interesting applications in the study of orthogonal polynomials. 相似文献
10.
The iterative method of the first author makes possible a self-correcting scheme for the approximate solution obtained. This scheme accelerates the convergence and substantially decreases the number of terms necessary in computation for applications involving either linear or nonlinear stochastic systems. A “feedback” term compensates for the approximation of the system inverse operator by a partial sum. Further, errors are determined in calculating the mean solution 〈y〉 and the correlation by using the approximations 〈φn〉 and 〈φn(t1)φn(t2)〉 , where φn represents n terms of the solution by the iterative method for stochastic differential equations. 相似文献
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12.
David S Jerison 《Journal of Functional Analysis》1981,43(1):97-142
For (x,y,t)∈n × n × , denote and . When α = n ? 2q, a represents the action of the Kohn Laplacian □b on q-forms on the Heisenberg group. For ?n < α < n, we construct a parametrix for the Dirichlet problem in smooth domains D near non-characteristic points of ?D. A point w of ?D is non-characteristic if one of X1,…, Xn, Y1,…, Yn is transverse to ?D at w. This yields sharp local estimates in the Dirichlet problem in the appropriate non-isotropic Lipschitz classes. The main new tool is a “convolution calculus” of pseudo-differential operators that can be applied to the relevant layer potentials, for which the usual asymptotic composition formula is false. Characteristic points are treated in Part II. 相似文献
13.
14.
Wolfgang Wasow 《Linear algebra and its applications》1977,18(2):163-170
Let A(x,ε) be an n×n matrix function holomorphic for |x|?x0, 0<ε?ε0, and possessing, uniformly in x, an asymptotic expansion , as ε→0+. An invertible, holomorphic matrix function P(x,ε) with an asymptotic expansion , as ε→0+, is constructed, such that the transformation y = P(x,ε)z takes the differential equation a positive integer, into , where B(x,ε) is asymptotically equal, to all orders, to a matrix in a canonical form for holomorphic matrices due to V.I. Arnold. 相似文献
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16.
Amitai Regev 《Advances in Mathematics》1982,46(2):230-240
An asymptotic formula, involving integrals, is given for certain combinatorial sums. By evaluating a multi-integral it is then found that as n → ∞, the codimensions cn(F2) and the trace codimensions tn(F2) of F2, the 2 × 2 matrices, are asymptotically equal: . 相似文献
17.
Hartmut Pecher 《Journal of Functional Analysis》1982,46(2):221-229
Given a solution of the Cauchy problem for nonlinear wave equations of the type in three space dimensions the asymptotic behaviour in time is considered. It is shown that for nonlinearities which behave like powers uniform decay holds with a certain rate depending on σ if , and moreover scattering states exist if σ is not too small. This improves former results of W. A. Strauss (J. Funct. Anal. 2 (1968), 409–457). 相似文献
18.
R.A. Adams 《Journal of Functional Analysis》1979,34(2):292-303
We obtain, for a large class of measures μ, general inequalities of the form , where , and the function A depends in an appropriate way on μ. Our results extend similar results obtained by Rosen for the case p = 2, A(t) = ts. We also investigate some implications of these inequalities for the imbedding of Sobolev spaces into Orlicz spaces. 相似文献
19.
Robert A. Morris 《Journal of Pure and Applied Algebra》1980,18(1):91-96
The absolute Kähler module of the truncated generalized Witt vectors of a field k of positive characteristic is zero if and only if k is perfect. This recovers known information on with which the structure of K2(k((t))) can be studied. 相似文献
20.
Robert Whitley 《Journal of Mathematical Analysis and Applications》1985,105(2):502-513
A complete proof, which yields an error term showing a dependence on n and x, is given for Bernstein's result that the best bound on the kth derivative on polynomials of degree less than or equal to n, at a point x in ( ?1, 1), is asymptotic to as n tends to infinity. 相似文献