共查询到20条相似文献,搜索用时 90 毫秒
1.
Yi-rangYuan 《应用数学学报(英文版)》2004,20(3):381-396
For compressible two-phase displacement problem,the modified upwind finite difference fractionalsteps schemes are put forward.Some techniques,such as calculus of variations,commutative law of multiplicationof difference operators,decomposition of high order difference operators,the theory of prior estimates and tech-niques are used.Optimal order estimates in L~2 norm are derived for the error in the approximate solution.Thismethod has already been applied to the numerical simulation of seawater intrusion and migration-accumulationof oil resources. 相似文献
2.
Starting with the relatively simple observation that the variational estimates of the commutators of the standard Calderón-Zygmund operators with the bounded mean oscillation(BMO) functions can be obtained from their weighted variational estimates, we establish the similar variational estimates for the commutators of the BMO functions with rough singular integrals, which do not admit any weighted variational estimates. The proof involves several Littlewood-Paley-type inequalities with the commutators as well as Bony decomposition and related para-product estimates. 相似文献
3.
Instead of the L~p estimates,we study the modulation space estimates for the solution to the damped wave equation.Decay properties for both the linear and semilinear equations are obtained.The estimates in modulation space differ in many aspects from those in L~p space. 相似文献
4.
Hermite interpolation and its numerical differentiation formula involving symmetric functions 总被引:1,自引:0,他引:1
By utilizing symmetric functions,this paper presents explicit representations for Hermite interpolation and its numerical differentiation formula.And the corresponding error estimates are also provided. 相似文献
5.
We consider a control-constrained parabolic optimal control problem without Tikhonov term in the tracking functional.For the numerical treatment,we use variational discretization of its Tikhonov regularization:For the state and the adjoint equation,we apply Petrov-Galerkin schemes in time and usual conforming finite elements in space.We prove a-priori estimates for the error between the discretized regularized problem and the limit problem.Since these estimates are not robust if the regularization parameter tends to zero,we establish robust estimates,which--depending on the problem's regularity——enhance the previous ones.In the special case of bang-bang solutions,these estimates are further improved.A numerical example confirms our analytical findings. 相似文献
6.
The authors obtain the estimates of all homogeneous expansions for a subclass of ε quasi-convex mappings on the unit ball in complex Banach spaces. Moreover, the estimates of all homogeneous expansions for the above generalized mappings on the unit polydisk in Cnare also obtained. Especially, the above estimates are only sharp for a subclass of starlike mappings, quasi-convex mappings and quasi-convex mappings of type A. The results are the generalization of many known results. 相似文献
7.
GENERALIZED LEAST SQUARES AND MAXIMUM LIKELIHOOD ESTIMATIONS OF MULTIVARIATE POLYCHORIC CORRELATIONS
This paper investigates the generalized least squares estimation and the maximum likelihoodestimation of the parameters in a multivariate polychoric correlations model,based on data from amultidimensional contingency table.Asymptotic properties of the estimators are discussed.An iterativeprocedure based on the Gauss-Newton algorithm is implemented to produce the generalized leastsquares estimates and the standard errors estimates.It is shown that via an iteratively reweightedmethod,the algorithm produces the maximum likelihood estimates as well.Numerical results on thefinite sample behaviors of the methods are reported. 相似文献
8.
We can compare the estimates from the linear approximations above, then we can find that the tangent line approximation gives good estimates whenxis close to 1. And 相似文献
9.
In this article,a procedure for estimating the coefficient functions on the functional-coefficient regression models with different smoothing variables in different coefficient functions is defined.First step,by the local linear technique and the averaged method,the initial estimates of the coefficient functions are given.Second step,based on the initial estimates,the efficient estimates of the coefficient functions are proposed by a one-step back-fitting procedure.The efficient estimators share the same asymptotic normalities as the local linear estimators for the functional-coefficient models with a single smoothing variable in different functions.Two simulated examples show that the procedure is effective. 相似文献
10.
Yu MIAO 《数学年刊B辑(英文版)》2007,28(5):555-570
In the present paper,the full range Strichartz estimates for homogeneous Schr(?)dinger equations with non-degenerate and non-smooth coefficients are proved.For inhomogeneous equation,the non-endpoint Strichartz estimates are also obtained. 相似文献
11.
Barvinok 《Foundations of Computational Mathematics》2008,2(4):393-412
Abstract. Let G be a compact group acting in a real vector space V . We obtain a number of inequalities relating the L
∞ norm of a matrix element of the representation of G with its L
2k
norm for a positive integer k . As an application, we obtain approximation algorithms to find the maximum absolute value of a given multivariate polynomial
over the unit sphere (in which case G is the orthogonal group) and for the assignment problem of degree d , a hard problem of combinatorial optimization generalizing the quadratic assignment problem (in which case G is the symmetric group). 相似文献
12.
Kenji Nishihara 《Mathematische Zeitschrift》2003,244(3):631-649
It has been asserted that the damped wave equation has the diffusive structure as t→∞. In this paper we consider the Cauchy problem in 3-dimensional space for the linear damped wave equation and the corresponding
parabolic equation, and obtain the L
p
−L
q
estimates of the difference of each solution, which represent the assertion precisely. Explicit formulas of the solutions
are analyzed for the proof. The second aim is to apply the L
p
−L
q
estimates to the semilinear damped wave equation with power nonlinearity. If the power is larger than the Fujita exponent,
then the time global existence of small weak solution is proved and its optimal decay order is obtained.
Received: 8 June 2001; in final form: 12 August 2002 /
Published online: 1 April 2003
Mathematical Subject Classification (2000): 35L15. 相似文献
13.
Given two doubling measures μ and ν in a metric space (S, ρ) of homogeneous type, let B
0⊂S be a given ball. It has been a well-known result by now (see [1–4]) that the validity of an L
1→L
1 Poincaré inequality of the following form:
for all metric balls B⊂B
0⊂S, implies a variant of representation formula of fractional integral type: for ρ-a.e. x∈B
0,
One of the main results of this paper shows that an L
1 to L
q
Poincaré inequality for some 0 < q < 1, i.e.,
for all metric balls B⊂B
0, will suffice to imply the above representation formula. As an immediate corollary, we can show that the weak-type condition,
also implies the same formula.
Analogous theorems related to high-order Poincaré inequalities and Sobolev spaces in metric spaces are also proved.
Received December 27, 2000, Accepted May 28, 2001 相似文献
14.
H. Mohebi 《Journal of Applied Mathematics and Computing》2000,7(2):465-475
We give various characterizations of pseudo-Chebyshev subspaces in the spacesL 1(S, μ) andC(T). 相似文献
15.
Yong Zhou 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2009,11(3):191-204
Considering the Navier–Stokes equations in
W ì \mathbbRn\Omega \subset {\mathbb{R}}^n, we prove the asymptotic stability for weak solutions in the marginal class u ∈ C
B
(0, ∞; L
n
) with arbitrary initial and external perturbations. 相似文献
16.
M. E. Ballve 《Rendiconti del Circolo Matematico di Palermo》1990,39(1):58-64
The object of this paper is to study the stability of the quasi-completeness of theL
α spaces for locally convex vector valued functions, by the inductive limits and the countable products. 相似文献
17.
V. Yu. Gubarev 《Siberian Mathematical Journal》2009,50(3):395-404
We take the exterior power ℝ4 ∧ ℝ4 of the space ℝ4, its mth symmetric power V = S
m
(∧2ℝ4) = (ℝ4 ∧ ℝ4) ∨ (ℝ4 ∧ ℝ4) ∨ ... ∨(ℝ4 ∧ ℝ4), and put V
0 = L((x ∧ y)∨ ... ∨(x ∧ y): x, y ∈ ℝ4). We find the dimension of V
0 and an algorithm for distinguishing a basis for V
0 efficiently. This problem arose in vector tomography for the purpose of reconstructing the solenoidal part of a symmetric
tensor field.
Original Russian Text Copyright ? 2009 Gubarev V. Yu.
The author was supported by the State Maintenance Program for the Leading Scientific Schools of the Russian Federation (Grant
NSh-344.2008.1).
__________
Novosibirsk. Translated from Sibirskiĭ Matematicheskiĭ Zhurnal, Vol. 50, No. 3, pp. 503–514, May–June, 2009. 相似文献
18.
This article gives the representations of two types of real functionals on L
∞(Ω, Ƒ) or L
∞(Ω, Ƒ, ℙ) in terms of Choquet integrals. These functionals are comonotonically subadditive and comonotonically convex, respectively. 相似文献
19.
Kyeong-Hun Kim 《Journal of Theoretical Probability》2008,21(1):169-192
Degenerate stochastic partial differential equations are considered in C
1 domains. Existence and uniqueness results are given in weighted Sobolev spaces, and H?lder estimates of the solutions are
presented.
This work was supported by a Korea University grant. 相似文献
20.
Mao Hua LE 《数学学报(英文版)》2008,24(6):917-924
Let a, b and c be fixed coprime positive integers. In this paper we prove that if a^2 + b^2 = c^3 and b is an odd prime, then the equation a^x + b^y = c^z has only the positive integer solution (x, y, z) = (2,2,3). 相似文献