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1.
We consider for a fixed μ, the class of polynomials
Pn,μ,s:+{P(z)=z^2(anz^n-s+∑j=μ^n-s an-jz^n-j-s);1≤μ≤n-s}
of degree n, having all zeros in | z| ≤ k, k≤ 1, with s-fold zeros at the origin. In this paper, we have obtained inequalities in the reverse direction for the above class of polynomials. Besides, extensions of some Turan-type inequalities for the polar derivative of polynomials have been considered.  相似文献   

2.
Using product and convolution theorems on Lorentz spaces, we characterize the sufficient and necessary conditions which ensure the validity of the doubly weighted Hardy-Littlewood-Sobolev inequality. It should be pointed out that we consider whole ranges of p and q, i.e., 0 p ≤∞ and 0 q ≤∞.  相似文献   

3.
Let Pn be the class of polynomials of degree at most nRather and Shah [15]proved that if P∈Pnand P(z)≠0 in|z| 1, then for every R 0 and 0≤q ∞,|B[ P( Rz)]|q ≤|RnB[zn] + λ0 |q|1 + zn|q|P(z)|q,where B is a Bn-operator.In this paper, we prove some generalization of this result which in particular yields some known polynomial inequalities as specialWe also consider an operator Dαwhich maps a polynomial P(z) into DαP(z) := n P(z) +(α-z) P′(z) and obtain extensions and generalizations of a number of well-known Lq inequalities  相似文献   

4.
In this paper, we study the sharp Jackson inequality for the best approximation of f ∈L2,κ(Rd) by a subspace E2κ(σ)(SE2κ(σ)), which is a subspace of entire functions of exponential type(spherical exponential type) at most σ. Here L2,κ(Rd) denotes the space of all d-variate functions f endowed with the L2-norm with the weight v2κ(x) =ξ∈R, which is defined by a positive+|(ξ, x)|κ(ξ)subsystem R+ of a finite root system RRdand a function κ(ξ) : R → R+ invariant under the reflection group G(R) generated by R. In the case G(R) = Zd2, we get some exact results. Moreover,the deviation of best approximation by the subspace E2κ(σ)(SE2κ(σ)) of some class of the smooth functions in the space L2,κ(Rd) is obtained.  相似文献   

5.
For a polynomial p(z) of degree n which has no zeros in |z| 1, Dewan et al.,(K. K. Dewan and Sunil Hans, Generalization of certain well known polynomial inequalities, J. Math. Anal. Appl., 363(2010), 38–41) established zp′(z) +nβ2p(z) ≤n2{( β2 + 1+β2)max|z|=1|p(z)|-( 1+β2- β2)min|z|=1|p(z)|},for any complex number β with |β|≤ 1 and |z| = 1. In this paper we consider the operator B, which carries a polynomial p(z) into B[ p(z)] := λ0p(z) + λ1(nz2)p′(z)1!+ λ2(nz2)2 p′′(z)2!,where λ0, λ1, and λ2are such that all the zeros of u(z) = λ0+c(n,1)λ1z+c(n,2)λ2z2lie in the half plane |z| ≤ |z-n/2|. By using the operator B, we present a generalization of result of Dewan. Our result generalizes certain well-known polynomial inequalities.  相似文献   

6.
In this article, some necessary and sufficient conditions are shown in order that the inequality of the form Ф1(λ)Pu(f^*〉λ)≤Ev (Ф2(C|f∞|)) holds with some constant C 〉 0 independent of martingale f = (fn)n≥0 and λ 〉 0, where Фl and Ф2 are a pair of Young functions, f^*=sup n≥0|fn| adn f∞=lim n→∞ fn a.e.  相似文献   

7.
The paper presents simple proofs of the Cauchy-Schwartz inequality and the negative discriminant property in archimedean almost f-algebras^[5], based on a sequence approximation.  相似文献   

8.
We discuss a class of complete Kaihler manifolds which are asymptotically complex hyperbolic near infinity. The main result is vanishing theorems for the second L2 cohomology of such manifolds when it has positive spectrum. We also generalize the result to the weighted Poincare inequality case and establish a vanishing theorem provided that the weighted function p is of sub-quadratic growth of the distance function. We also obtain a vanishing theorem of harmonic maps on manifolds which satisfies the weighted Poincare inequality.  相似文献   

9.
Furuta showed that if A≥B≥0,then for each r≥0,f(p)=(A^r/2 B^p A^r/2)^t+r/p+r is decreasing for p≥t≥0.Using this result,the following inequality(C^r/2(AB^2A)^δC^ r/2)^ p-1+r/4δ+r ≤C^p-1+r is obtained for 0〈p ≤1,r≥1,1/4≤δ≤1 and three positive operators A, B, C satisfy(A^1/2BA^1/2)^p/2≤A^p,(B^1/2AB^1/2)^p/2≥B^p,(C^1/2AC^1/2)^p/2≤C^p,(A^1/2CA^1/2)^p/2≥A^p.  相似文献   

10.
In this paper, the complete noncompact Kahler manifolds satisfying the weighted Poincare inequality are considered and one nonparabolic end theorem which generalizes Munteanu's result is obtained.  相似文献   

11.
A generalized Rosenthal's inequality for Banach-space-valued martingales is proved, which extends the corresponding results in the previous literatures and characterizes the p-uniform smoothness and q-uniform convexity of the underlying Banach space. As an application of this inequality, the strong law of large numbers for Banach-space-valued martingales is also given.  相似文献   

12.
C.  Jaiboon  P  Kumam  U.  W.  Humphries 《逼近论及其应用》2009,(4):381-400
The purpose of this paper is to investigate the problem of finding the common element of the set of common fixed points of a countable family of nonexpansive mappings, the set of an equilibrium problem and the set of solutions of the variational inequality prob- lem for a relaxed cocoercive and Lipschitz continuous mapping in Hilbert spaces. Then, we show that the sequence converges strongly to a common element of the above three sets under some parameter controlling conditions, which are connected with Yao, Liou, Yao[17], Takahashi[12] and many others.  相似文献   

13.
In this paper, We study a general class of nonlinear degenerated elliptic problems associated with the differential inclusion β(u)-div(a(x, Du)+ F(u)) ■ f in Ω, where f ∈ L1 Ω. A vector field a(·,·) is a Carath′eodory function. Using truncation techniques and the generalized monotonicity method in the functional spaces we prove the existence of renormalized solutions for general L1-data. Under an additional strict monotonicity assumption uniqueness of the renormalized solution is established.  相似文献   

14.
P(z)=∑v=0^n cvz^v
be a polynomial of degree n and let M(f, r) = max|z|=r |f(z) | for an arbitrary entire function f(z). If P(z) has no zeros in |z| 〈 1 with M(P,1) = 1, then for |α| 〈 1, it is proved by Jain[Glasnik Matematicki, 32(52) (1997), 45-51] that
|P(Rz)+α(R+1/2)^nP(z)|≤1/2{|1+α(R+1/2)^n|+|R^n+α((R+1/2)^n|},R≥1,|z|=1.
In this paper, we shall first obtain a result concerning minimum modulus of polynomials and next improve the above inequality for polynomials with restricted zeros. Our result improves the well known inequality due to Ankeny and Rivlin and besides generalizes some well known polynomial inequalities proved by Aziz and Dawood.  相似文献   

15.
We obtain the optimal integrability for positive solutions of the Euler-Lagrange system of the weighted Hardy-Littlewood-Sobolev inequality in R^n :{u(x)=1/|x|^α|∫R^n v(y)^q|y|^β|x-y|^λdy,v(x)=1/|x|^β∫R^n u(y)^p|y|^α|x-y|^λdy.C. Jin and C. Li [Calc. Var. Partial Differential Equations, 2006, 26: 447-457] developed some very interesting method for regularity lifting and obtained the optimal integrability for p, q 〉 1. Here, based on some new observations, we overcome the difficulty there, and derive the optimal integrability for the case of p, q ≥1 and pq ≠1. This integrability plays a key role in estimating the asymptotic behavior of positive solutions when |x| →0 and when |x|→∞.  相似文献   

16.
This note addresses monotonic growths and logarithmic convexities of the weighted((1-t2)αdt2,-∞α∞,0t1)integral means Aα,β(f,)and Lα,β(f,)of the mixed area(πr2)-βA(f,r)and the mixed length(2πr)-βL(f,r)(0≤β≤1 and0r1)of f(rD)and f(rD)under a holomorphic map f from the unit disk D into the finite complex plane C.  相似文献   

17.
In this paper, we obtain the Hejek-Renyi-type inequality for a class of random variable sequences and give some applications for associated random variable sequences, strongly positive dependent stochastic sequences and martingale difference sequences which generalize and improve the results of Prakasa Rao and Soo published in Statist. Probab. Lett., 57(2002) and 78(2008). Using this result, we get the integrability of supremum and the strong law of large numbers for a class of random variable sequences.  相似文献   

18.
In this paper, we establish a fixed point theorem for set-valued mapping on a topological vector space without "local convexity". And we also establish some generalized Ky Fan's minimax inequalities for set-value vector mappings, which are the generalization of some previous results.  相似文献   

19.
In this paper, we estimate the constants in the inverse inequalities for the finite ele- ment functions. Furthermore, we obtain the least upper bounds of the constants in inverse inequalities for the low-order finite element functions. Such explicit estimates of the con- stants can be used as computable error bounds for the finite element method.  相似文献   

20.
Let r =2^d-1 + 1. We investigate the diophantine inequality
|∑i=1^r λiФi(xi,yi)+η|〈(max 1≤i≤r{|xi|,|yi|})^-δ,
where Фi(x,y)∈X[x,y](1≤i≤r) are nondegenerate forms of degree d = 3 or 4.  相似文献   

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