共查询到20条相似文献，搜索用时 46 毫秒
1.
The paper deals with the problem of recovering the parameters (functions)
and
of the Maxwell dynamical system
(tan is the tangent component;
is a solution) by the response operator
(
is the normal). The parameters determine the velocity
, the c-metric
, and the time
. It is shown that for any fixed
, the operator
determines
and
in
uniquely. Bibliography: 15 titles. 相似文献
2.
J Feuer E.J. Janowski G Ladas C Teixeira 《Journal of Computational Analysis and Applications》2000,2(3):237-252
We investigate the asymptotic behavior, the oscillatory character, and theperiodic nature of solutions of the difference equation
where
is a real parameter and the initial conditions arearbitrary nonzero real numbers. 相似文献
3.
S. R. Grace 《Czechoslovak Mathematical Journal》2000,50(2):347-358
4.
Ram U. Verma 《Journal of Computational Analysis and Applications》2002,4(3):177-192
Consider the convergence of the projection methods based on an extension of a special class of algorithms for the approximation--solvability of the following class of nonlinear quasivariational inequality (NQVI) problems: find an element
such that
and
where
are mappings on H and K is a nonempty closed convex subset of a real Hilbert space H. The iterative procedure is characterized as a nonlinear quasivariational inequality: for any arbitrarily chosen initial point x
0 K and, for constants
0$$
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and
0$$
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, we have
where
This nonlinear quasivariational inequality type algorithm has an equivalent projection formula
where
for the projection P
K
of H onto K. 相似文献
5.
Frank Filbir Roland Girgensohn Anu Saxena Ajit Iqbal Singh Ryszard Szwarc 《Journal of Computational Analysis and Applications》2000,2(2):177-213
For an orthogonal polynomial system
and a sequence
of nonzero numbers,let
be the linear operator defined on the linear spaceof all polynomials via
for all
.We investigate conditions on
and
under which
can simultaneously preserve the orthogonality ofdifferent polynomial systems. As an application, we get that for
, a generalized Laguerre polynomial system, no
can simultaneously preserve the orthogonality of twoadditional Laguerre systems,
and
, where
and
. On the other hand, for
,the Chebyshev polynomial system and
,
simultaneously preserves the orthogonality of uncountablymany kernel polynomial systems associated with p. We study manyother examples of this type. 相似文献
6.
Qi S. Zhang 《Journal of Computational Analysis and Applications》2000,2(4):277-292
We study the inhomogeneous semilinear wave equations
on
with initial values
and
,where
is a noncompact, complete manifold. We founda new critical behavior in the following sense. There exists ap* > 0. When 1 < p p*, the above problem hasno global solution for any nonnegative
not identicallyzero and for any
and
; when
the problem has a global solution for some
and some
and
. If
, which is equipped with the Euclideanmetric, then
. If
we show that
belongs to the blow upcase. Although homogeneous semilinear wave equations are known to exhibit acritical behavior for a long time, this seems to be the first result oninhomogeneous ones. 相似文献
7.
In what follows, $C$ is the space of
-periodic continuous functions; P is a seminorm defined on C, shift-invariant, and majorized by the uniform norm;
is the mth modulus of continuity of a function f with step h and calculated with respect to P;
,
(
),
,
,
Theorem 1.
Let
. Then
For some values of
and seminorms related to best approximations by trigonometric polynomials and splines in the uniform and integral metrics, the inequalities are sharp. Bibliography: 6 titles. 相似文献
8.
Estimates for deviations are established for a large class of linear methods of approximation of periodic functions by linear combinations of moduli of continuity of different orders. These estimates are sharp in the sense of constants in the uniform and integral metrics. In particular, the following assertion concerning approximation by splines is proved: Suppose that
is odd,
. Then
moreover, for
it is impossible to decrease the constants on
. Here,
are some explicitly constructed constants,
is the modulus of continuity of order r for the function f, and
are explicitly constructed linear operators with the values in the space of periodic splines of degree
of minimal defect with 2n equidistant interpolation points. This assertion implies the sharp Jackson-type inequality
. Bibliography: 17 titles. 相似文献
9.
G. I. Laptev 《Journal of Mathematical Sciences》2005,129(1):3617-3625
We study the conditions for the existence and nonexistence of global in time (t > 0), nonnegative solutions of the problem
If p + q ≤ 2 + 2/N, then the problem has no global nontrivial solutions. If p + q > 2 + 2/N, then such solutions exist. Some generalizations of this problem are discussed.__________Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 10, Suzdal Conference-4, 2003. 相似文献
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10.
Y. Rakotondratsimba 《Acta Mathematica Hungarica》2000,86(3):213-236
A sufficient condition on nonnegative double-sequences
is derived in order that the two-dimensional discrete Hardy operator His bounded from
into
whenever 1 < p q < . 相似文献
11.
Let u(x) xR
q
be a symmetric nonnegative definite function which is bounded outside of all neighborhoods of zero but which may have u(0)=. Let p
x, (·) be the density of an R
q
valued canonical normal random variable with mean x and variance and let {G
x, ; (x, )R
q
×[0,1 ]} be the mean zero Gaussian process with covariance
A finite positive measure on R
q
is said to be in
with respect to u, if
When
, a multiple Wick product chaos
is defined to be the limit in L
2, as 0, of
where
,
denotes the Wick product of the m
j
normal random variables
.Consider also the associated decoupled chaos processes
,
defined as the limit in L
2, as 0, of
where
are independent copies of G
x,.Define
Note that a neighborhood of the diagonals of
in
is excluded, except those points on the diagonal which originate in the same Wick product in (i). Set
One of the main results of this paper is:
Theorem A. If
is continuous on (R
q
)
r
for all
then
is continuous on
.When u satisfies some regularity conditions simple sufficient conditions are obtained for the continuity of
on (R
q
)
r
. Also several variants of (i) are considered and related to different types of decoupled processes. These results have applications in the study of intersections of Lévy process and continuous additive functionals of several Lévy processes. 相似文献
12.
A generalized interpolation polynomial with a base function
and node coefficients
, is a polynomial of the form
where the system of functions
forms a Chebyshev system on [a,b]. In this article, we show that by using the polynomials g(x) one can construct both adaptive quadrature formulas that optimize the quadrature error and piecewise-smooth stable solutions of the Cauchy problem. 相似文献
13.
14.
O. L. Vinogradov 《Journal of Mathematical Sciences》2004,120(5):1662-1671
Let
be the Jacobi polynomials and let C[a,b] be the space of continuous functions on [a,b] with the uniform norm. In this paper, we study sequences of Lebesgue constants, i.e., of the norms of linear operators
generated by a multiplier matrix
defined by the following relations:
and
In the case || = || = 1/2, we prove the following statements for the Jacobi polynomials (these statements are similar to known results for the trigonometrical system). Consider the cases
and
Under some conditions on a function , the values
and
equal
and
In addition, we show that for the Fourier–Legendre summation methods ( = = 0) generated by the multiplier function
, the limit and supremum of the sequence of Lebesgue constants may differ. Bibliography: 11 titles. 相似文献
15.
Satoshi Tanaka 《Czechoslovak Mathematical Journal》2001,51(3):573-583
The higher order neutral functional differential equation
is considered under the following conditions:
is strictly increasing in
is nonnegative on
and nondecreasing in
. A necessary and sufficient condition is derived for the existence of certain positive solutions of (1). 相似文献
16.
This paper considers the approximation of the Kantorovich–Shepard operators in
spaces for
. For
the Kantorovich–Shepard operators
are defined by (1.1). Then
where
is a positive number depending only on
and , and $$ \varepsilon_{n} =\cases{ n^{-1}, & if \
2$$
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; \cr\nosm n^{-1}\log n, & if \
; \cr\nosm n^{1-\lambda}, & if \
. \cr} $$ 相似文献
17.
An analog of the classical Fourier formula for the characteristic function of a convex compact set
is considered:
where W is a polyhedral in
. Bibliography: 6 titles. 相似文献
18.
Let
be a C*-algebra and X a Hilbert C*
-module. If
is a projection, let
be the p-sphere of X. For φ a state of
with support p in
and
consider the modular vector state φx of
given by
The spheres
provide fibrations
and
These fibrations enable us to examine the homotopy type of the sets of modular vector states, and relate it to the homotopy type of unitary groups and spaces of projections. We regard modular vector states as generalizations of pure states to the context of Hilbert C*-modules, and the above fibrations as generalizations of the projective fibration of a Hilbert space. 相似文献
19.
O. M. Fomenko 《Journal of Mathematical Sciences》2004,122(6):3679-3684
Let
, and let
be Epstein's zeta-function of the form Q. It is proved that for |t| > C > 0 one has the estimate
Bibliography: 9 titles. 相似文献
20.
Let
We show that for every function
satisfying the conditional equation
either there exists a solution
of the Goab-Schinzel equation
such that
(i.e., f(x) = g(x) for
) or there is x0 > 0 with f(x0) < –1 and f(x) = 0 for x x0 . In particular we determine the solutions
of the conditional equation that are continuous at a point, Lebesgue measurable or Baire measurable (i.e., have the Baire property). In this way we solve some problems raised by the first author.Received: 2 March 2004 相似文献
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