Note on an Iyengar type inequality

Using Hayashi’s inequality, an Iyengar type inequality for functions with bounded second derivative is obtained. This result improves a similar result from [N. Elezović, J. Pečarić, Steffensen’s inequality and estimates of error in trapezoidal rule, Appl. Math. Lett. 11 (6) (1998) 63–69] and, for some classes of functions, the result from [X.L. Cheng, The Iyengar type inequality, Appl. Math. Lett. 14 (2001) 975–978].     

On weighted Iyengar type inequalities on time scales

In this study, we establish some new weighted Iyengar type integral inequalities using Steffensen’s inequality on time scales.     

一个新的带参数的Hilbert型积分不等式

本文研究Hilbert积分不等式的推广问题.利用引入参数和对数积分核函数,建立了一种新的Hilbert型积分不等式,证明了用Euler数和π来表示的常数因子是最佳的,推广了经典的Hilbert积分不等式.     

The Iyengar inequality,revisited

Detailed analysis shows that the famous Iyengar inequality actually says that the Trapezoidal formula is a central algorithm for approximating integrals over an appropriate interval for the class of functions whose derivatives are bounded by a positive number K in L _∞-sense. The inherent nonlinearity from central algorithms reflects the importance of the Iyengar inequality and thus makes familiar linear methods malfunction when one tries to generalize it. It is shown that the generalization depends on a nonlinear system of equations satisfied by a set of free nodes of a perfect spline. Explicit constructions are obtained in the spirit of the Iyengar inequality for the class of functions whose rth (r≤4) derivatives are bounded by a positive number K in L _∞-sense because a closed solution to the nonlinear system is only available for r≤4. Connections with computational mathematics, especially with best interpolation and best quadrature, are discussed. Numerical experiments are also included. AMS subject classification (2000)  65D30, 41A17     

A new integral inequality with power nonlinearity and its discrete analogue

1. IntroductionIt is well known that integral inequalities are very crucial in the study of differelltialequations, integral equations, functional-differential equations, iniegro-differential equationsand evolution equations. Besides the famous Gronwall-Bellman inequality and its first nonlinear generalization due to i. Bihari (of. [1]), there is another very useful integral inequalityestablished by L. On-fang[2]:Lemma 1. Let u(t) and h(t) be real-valued, nonnegative and continuous functions…     

Hardy-Littlewood不等式的一些推广与应用

利用H\"{o}lder不等式和β-函数, 得到了Hardy-Littlewood不等式的一些推广和改进形式. 作为应用, 通过所得结果及矩阵方法, 给出了Hilbert型不等式的一些推广和改进.     

Fan Ky不等式的一个新改进

利用Gram矩阵的正定性和可变单位向量建立了Fan Ky不等式的一个新的改进,并且建立了反向Fan Ky不等式.对于非奇异矩阵,得到了Fan Ky不等式以及反向Fan Ky不等式的推广.     

Constrained Kantorovich inequalities and relative efficiency of least squares

This paper establishes a type of Kantorovich inequality subject to some constraints and obtains some lower bounds for the relative efficiency of the least squares. These lower bounds can be much sharper than that obtained by using the unconstrained Kantorovich inequality. Multivariate extensions of the results are also obtained. Some interesting examples are presented.     

Some results on extending and sharpening the Weierstrass product inequalities

In this paper, we establish two extensions of Weierstrass's inequality involving symmetric functions by means of the theory of majorization, and give an interesting sharpness of Weierstrass's inequality by using the arithmetic-geometric mean inequality. Furthermore, we apply these results to improve a well-known inequality and deduce some new inequalities.     

一个不等式的简单证明与推广

本文讨论了一个引人注目而被广泛讨论的、与平均值有关的不等式.我们首先获得了它的完整形式,给出了一个非常简洁而能揭示问题本质的证明.由此我们自然地引出了它的最为一般的形式.同时,我们还指出文献中存在的一些谬误.     

Riemann zeta function and Lyapunov-type inequalities for certain higher order differential equations

This note generalizes the well known Lyapunov-type inequalities for second-order linear differential equations to certain 2M-th order linear differential equations with five types of boundary conditions. The usage of the best constant of some Sobolev-type inequalities clarify the process for obtaining such inequality and sharpen the result of Çakmak [2].     

On Carlson–Levin inequalities

We present a new proof of Carlson–Levin inequality and some of its extensions, based on a dynamic programing-type approach.     

The optimal constant in Wente's $ L^\infty $ estimate

We explore some geometric aspects of compensation compactness associated to Jacobian determinants. We provide the optimal constant in Wente's inequality - the original motivation of this work - and go on to give various extensions to geometric situations. In fact we improve Wente's inequality somewhat, making it more appropriate for applications in which optimal results are required. This is demonstrated when we prove an optimal inequality for immersed surfaces of constant mean curvature in , contolling their diameter in terms of their area and curvature. Received: November 4, 1996     

Extension of Hilbert's inequality

In this paper we make some further extensions of discrete Hilbert's inequality by using Euler-Maclaurin summation formula. We give the improvements of some previously obtained results and also compare our results with some previously known from the literature.     

Projections, entropy and sumsets

In this paper we shall generalize Shearer??s entropy inequality and its recent extensions by Madiman and Tetali, and shall apply projection inequalities to deduce extensions of some of the inequalities concerning sums of sets of integers proved recently by Gyarmati, Matolcsi and Ruzsa. We shall also discuss projection and entropy inequalities and their connections.     

Reflexivity and Ring Homomorphisms of Finite Flat Dimension

In this article we present a systematic study of the reflexivity properties of homologically finite complexes with respect to semidualizing complexes in the setting of nonlocal rings. One primary focus is the descent of these properties over ring homomorphisms of finite flat dimension, presented in terms of inequalities between generalized G-dimensions. Most of these results are new even when the ring homomorphism is local. The main tool for these analyses is a nonlocal version of the amplitude inequality of Iversen, Foxby, and Iyengar. We provide numerous examples demonstrating the need for certain hypotheses and the strictness of many inequalities.     

Best proximity point theorems generalizing the contraction principle

The primary objective of this article is to elicit some interesting extensions of the simple but powerful Banach’s contraction principle to the case of non-self-mappings. In fact, due to the fact that best proximity point theorems fit the bill to this end, the proposed extensions are presented as best proximity point theorems for non-self proximal contractions which are more general than the notion of self-contractions.     

Boundary Extensions of Mappings Satisfying the Poletsky Inverse Inequality in Terms of Prime Ends

Ukrainian Mathematical Journal - For mappings with branching points satisfying the Poletsky inverse inequality, we obtain some results on their continuous boundary extensions in terms of prime...     

On a strengthened multidimensional Hilbert-type inequality

The main objective of this paper is a study of the general refinement and converse of the multidimensional Hilbert-type inequality in the so-called quotient form. Such extensions are deduced with the help of the sophisticated use of the well-known Hölder’s inequality. The obtained results are then applied to homogeneous kernels with the negative degree of homogeneity. Also, we establish the conditions under which the constant factors involved in the established inequalities are the best possible. Finally, we consider some particular settings with homogeneous kernels and weighted functions. In such a way we obtain both refinements and converses of some actual results, known from the literature.     

On some new Hilbert-type inequalities

In the present paper we establish some new inequalities similar to extensions of Hilbert’s double-series inequality and give also their integral analogues. Our results provide some new estimates to these types of inequalities.