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1.
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$$ " align="middle" border="0"> and 0$$ " align="middle" border="0"> , 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   

2.
In this paper we investigate commutativity of rings with unity satisfying any one of the properties:
for some f(X) in and g(X), h(X) in where m 0, r 0, s 0, n > 0, t > 0 are non-negative integers. We also extend these results to the case when integral exponents in the underlying conditions are no longer fixed, rather they depend on the pair of ring elements x and y for their values. Further, under different appropriate constraints on commutators, commutativity of rings has been studied. These results generalize a number of commutativity theorems established recently.  相似文献   

3.
Let be sequences of real numbers which are symmetric in k. Let be independent sequences of independent normal random variables with mean zero and variance one. For each fixed choice of we consider
Let
Several examples are given in which the condition
is either a sufficient, a necessary, or a necessary and sufficient condition for {Q(x), x[0, 2] n } to have a continuous version.  相似文献   

4.
We prove the existence of continuously differentiable solutions such that
or
where
  相似文献   

5.
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   

6.
A Littlewood-Paley type inequality   总被引:2,自引:0,他引:2  
In this note we prove the following theorem: Let u be a harmonic function in the unit ball and . Then there is a constant C = C(p, n) such that
.  相似文献   

7.
Newton's binomial theorem is extended to an interesting noncommutative setting as follows: If, in a ring,ba=ab with commuting witha andb, then the (generalized) binomial coefficient arising in the expansion
  相似文献   

8.
Let = (1,...,d) be a vector with positive components and let D be the corresponding mixed derivative (of order j with respect to the jth variable). In the case where d > 1 and 0 < k < r are arbitrary, we prove that
and
for all Moreover, if is the least possible value of the exponent in this inequality, then
Deceased.Translated from Ukrainskyi Matematychnyi Zhurnal, Vol. 56, No. 5, pp. 579–594, May, 2004.  相似文献   

9.
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   

10.
In this work we investigate some oscillatory properties of solutions of non-linear differential systems with retarded arguments. We consider the system of the form
where n 3 is odd, > 0, > 0.This research was supported by the grants 1/8055/01 and 1/0026/03 of Scientific Grant Agency of Ministry of Education of Slovak Republic and Slovak Academy of Sciences.  相似文献   

11.
For f L n (T d ) and , the modulus of smoothness
is shown to be equivalent to
where T n is the best trigonometric polynomial approximant of degree n to f in L p and is the Laplacian. The above result is shown to be incorrect for 0 < p .  相似文献   

12.
We investigate the relationship between the constants K(R) and K(T), where is the exact constant in the Kolmogorov inequality, R is the real axis, T is a unit circle,
is the set of functions x L p(G) such that x (r) L s(G), q, p, s [1, ], k, r N, k < r, We prove that if
thenK(R) = K(T),but if
thenK(R) K(T); moreover, the last inequality can be an equality as well as a strict inequality. As a corollary, we obtain new exact Kolmogorov-type inequalities on the real axis.  相似文献   

13.
In this paper we consider the Cauchy problem for the hyperbolic system
0,t \geqslant 0} \\ {u_t + \tfrac{1}{2}(a^2 + u^2 )_x = 0} \\ \end{array} } \right.$$ " align="middle" vspace="20%" border="0">
with null boundary conditions and we prove a local (in time) existence and uniqueness theorem inC b 0, 1 and, for a special class of initial data, a blow-up result.Dedicated to Constantine Dafermos on his 60th birthdayThis research was supported by FCT and FEDER.  相似文献   

14.
A number of results on the average values of the class numbers of indefinite binary quadratic forms with discriminants divisible by a large square are proved. The main result is as follows. Let d = 4n 2 + 1. Then
where h(d) is the class number for the discriminant d and means that the summation is performed over the square-free d only. Bibliography: 9 titles.  相似文献   

15.
Qualitative comparison of the nonoscillatory behavior of the equations
and
is sought by way of finding different nonoscillation criteria for the above equations, L n is a disconjugate operator of the form
Both canonical and noncanonical forms of L n have been studied.  相似文献   

16.
Let {X n } n0 be a Harris recurrent Markov chain with state space E, transition probability P(x, A) and invariant measure , and let f be a real measurable function on E. We prove that with probability one,
under some best possible conditions.  相似文献   

17.
We obtain the new exact Kolmogorov-type inequality
for 2-periodic functions and any k, r N, k < r. We present applications of this inequality to problems of approximation of one class of functions by another class and estimates of K-functional type.  相似文献   

18.
Let r k(n) denote the number of representations of an integer n as a sum of k squares. We prove that
where
Here n = 2 p p p is the prime factorisation of n, n is the square-free part of n, the products are taken over the odd primes p, and ( ) is the Legendre symbol.Some similar formulas for r 7(n) and r 9(n) are also proved.  相似文献   

19.
Let be a primitive character mod k, k > 2. In [1], the following elementary estimate
was given, where
by definition. In the present note we sharpen this estimate by a factor 3/4 in the case of an even primitive character , by improving upon the proof given in [1] in a way which does not alter the elementary character of the method.  相似文献   

20.
Uniform Approximation of Nonperiodic Functions Defined on the Entire Axis   总被引:1,自引:1,他引:0  
Using the following notation: C is the space of continuous bounded functions f equipped with the norm , V is the set of functions f such that , the set E consists of fCV and possesses the following property:
is summable on each finite interval, we establish some assertions similar to the following theorem: Let 0$$ " align="middle" border="0"> ,
Then for fV the series
uniformly converges with respect to and the following equality holds:
This theorem develops some results obtained by Zubov relative to the approximation of probability distributions. Bibliography: 4 titles.  相似文献   

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