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1.
2.
We study the conditions for the existence and nonexistence of global in time (t > 0), nonnegative solutions of the problem
0,$$ " align="middle" vspace="20%" border="0">
1,\quad q > 0.$$ " align="middle" vspace="20%" border="0">
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   

3.
We study the limit as n goes to +∞ of the renormalized solutions u n to the nonlinear elliptic problems
where Ω is a bounded open set of ℝ N , N≥ 2, and μ is a Radon measure with bounded variation in Ω. Under the assumption of G-convergence of the operators , defined for , to the operator , we shall prove that the sequence (u n ) admits a subsequence converging almost everywhere in Ω to a function u which is a renormalized solution to the problem
  相似文献   

4.
Let Sn = X1 + · · · + X n , n ≥ 1, and S 0 = 0, where X 1, X 2, . . . are independent, identically distributed random variables such that the distribution of S n/B n converges weakly to a nondeoenerate distribution F α as n → ∞ for some positive B n . We study asymptotic behavior of sums of the form
where
a function d(t) is continuous at [0,1] and has power decay at zero,
Bibliography: 13 titles. Translated from Zapiski Nauchnylch Serninarov POMI, Vol. 361, 2008, pp. 109–122.  相似文献   

5.
In this paper, we are concerned with the global behavior ofthe solutions of the difference equation
where
and . Necessary and sufficient conditions for boundedness, persistence,and periodicity of all solutions will be established. The oscillatorybehavior will be investigated.  相似文献   

6.
There are many studies on the asymptotic behavior of solutions of differential equations. In the present paper, we consider another aspect of this problem, namely, the rate of the asymptotic convergence of solutions. Let ϕ (t) be a scalar continuous monotonically increasing positive function tending to ∞ as t → ∞. It is established that if all solutions of a differential system satisfy the inequality
then the solution x(t; t 0, x 0) of this differential system tends to 0 faster than .__________Published in Ukrains’kyi Matematychnyi Zhurnal, Vol. 57, No. 1, pp. 137–142, January, 2005.  相似文献   

7.
For a trigonometric series
defined on [−π, π) m , where V is a certain polyhedron in R m , we prove that
if the coefficients a k satisfy the following Sidon-Telyakovskii-type conditions:
Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 60, No. 5, pp. 579–585, May, 2008.  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.
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   

10.
Barrucand  P.  Cooper  S.  Hirschhorn  M.D. 《The Ramanujan Journal》2002,6(3):347-367
Let r k(n) denote the number of representations of n as a sum of k squares. We give many cases (for k = 5, 6, 7) in which the generating function n0 r k(an + b)q n is a simple infinite product. For instance,
  相似文献   

11.
Much recent work has been done to investigate convergence of modified continued fractions (MCF's), following the proof by Thron and Waadeland [35] in 1980 that a limit-periodic MCFK(a n , 1;x 1), with andnth approximant
  相似文献   

12.
The paper is concerned with oscillation properties of n-th order neutral differential equations of the form
0,$$ " align="middle" vspace="20%" border="0">
where c is a real number with with (t) < t and .Sufficient conditions are established for the existence of positive solutions and for oscillation of bounded solutions of the above equation. Combination of these conditions provides necessary and sufficient conditions for oscillation of bounded solutions of the equation. Furthermore, the results are generalized to equations in which c is a function of t and a certain type of a forcing term is present.  相似文献   

13.
Let an n × n Hermitian matrix A be presented in block 2 × 2 form as , where A12 ≠ 0, and assume that the diagonal blocks A11 and A22 are positive definite. Under these assumptions, it is proved that the extreme eigenvalues of A satisfy the bounds
where and ‖ ⋅ ‖ is the spectral norm. Further, in the positive-definite case, several equivalent conditions necessary and sufficient for both of the above bounds to be attained are provided. Bibliography: 6 titles.__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 301, 2003, pp. 172–194.  相似文献   

14.
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   

15.
For a sequence of identically distributed negatively associated random variables {Xn; n ≥ 1} with partial sums Sn = ∑i=1^n Xi, n ≥ 1, refinements are presented of the classical Baum-Katz and Lai complete convergence theorems. More specifically, necessary and sufficient moment conditions are provided for complete moment convergence of the form ∑n≥n0 n^r-2-1/pq anE(max1≤k≤n|Sk|^1/q-∈bn^1/qp)^+〈∞to hold where r 〉 1, q 〉 0 and either n0 = 1,0 〈 p 〈 2, an = 1,bn = n or n0 = 3,p = 2, an = 1 (log n) ^1/2q, bn=n log n. These results extend results of Chow and of Li and Spataru from the indepen- dent and identically distributed case to the identically distributed negatively associated setting. The complete moment convergence is also shown to be equivalent to a form of complete integral convergence.  相似文献   

16.
Our first basic model is the fully nonlinear dual porous medium equation with source
for which we consider the Cauchy problem with given nonnegative bounded initial data u0. For the semilinear case m=1, the critical exponent was obtained by H. Fujita in 1966. For p ∈(1, p0] any nontrivial solution blows up in finite time, while for p > p0 there exist sufficiently small global solutions. During last thirty years such critical exponents were detected for many semilinear and quasilinear parabolic, hyperbolic and elliptic PDEs and inequalities. Most of efforts were devoted to equations with differential operators in divergent form, where classical techniques associated with weak solutions and integration by parts with a variety of test functions can be applied. Using this fully nonlinear equation, we propose and develop new approaches to calculating critical Fujita exponents in different functional settings. The second models with a “semi-divergent” diffusion operator is the thin film equation with source
for which the critical exponent is shown to be   相似文献   

17.
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   

18.
The paper is devoted to study the asymptotic behaviour of zerosz n of an entire function of Mittag-Leffler's type
0,\mu \in C.}}} \right. \kern-\nulldelimiterspace} {\Gamma (\mu + {n \mathord{\left/ {\vphantom {n \rho }} \right. \kern-\nulldelimiterspace} \rho }),\rho > 0,\mu \in C.}}}$$ " align="middle" vspace="20%" border="0">  相似文献   

19.
In the present paper, the following Dirichlet problem and Neumann problem involving the p-Laplacian
((1.λ))
and
((2.λ))
are studied and some new multiplicity results of solutions for systems (1.λ) and (2.λ) are obtained. Moreover, by using the KKM principle we give also two new existence results of solutions for systems (1.1) and (2.1). This Work is supported in part by the National Natural Science Foundation of China (10561011).  相似文献   

20.
A Supplement to the Baum-Katz-Spitzer Complete Convergence Theorem   总被引:1,自引:0,他引:1  
Let {X, Xn; n≥ 1} be a sequence of i.i.d. Banach space valued random variables and let {an; n ≥ 1} be a sequence of positive constants such that an↑∞ and 1〈 lim inf n→∞ a2n/an≤lim sup n→∞ a2n/an〈∞ Set Sn=∑i=1^n Xi,n≥1.In this paper we prove that ∑n≥1 1/n P(||Sn||≥εan)〈∞ for all ε〉0 if and only if lim n→∞ Sn/an=0 a.s. This result generalizes the Baum-Katz-Spitzer complete convergence theorem. Combining our result and a corollary of Einmahl and Li, we solve a conjecture posed by Gut.  相似文献   

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