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相关论文: Some monotonicity rules for quotient of integrals …

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We prove new l'Hopital rules for monotonicity valid on an arbitrary time scale. Both delta and nabla monotonic l'Hopital rules are obtained. As an example of application, we give some new upper and lower bounds for the exponential function…

经典分析与常微分方程 · 数学 2010-11-23 Natalia Martins , Delfim F. M. Torres

The objective of this paper is twofold: (i) to survey existing results of generalized polynomials on time scales, covering definitions and properties for both delta and nabla derivatives; (ii) to extend previous results by using the more…

经典分析与常微分方程 · 数学 2008-09-10 Dorota Mozyrska , Delfim F. M. Torres

The theory of the calculus of variations was recently extended to the more general time scales setting, both for delta and nabla integrals. The primary purpose of this paper is to further extend the theory on time scales, by establishing…

经典分析与常微分方程 · 数学 2008-09-10 Rui A. C. Ferreira , Moulay Rchid Sidi Ammi , Delfim F. M. Torres

The main objective of this paper is to establish the $Y$-function and L'Hospital-type monotonicity rules with nabla and diamond-alpha derivatives on time scales.

经典分析与常微分方程 · 数学 2024-01-24 Xiao-Yue Du , Zhong-Xuan Mao , Jing-Feng Tian

The theory and applications of dynamic derivatives on time scales has recently received considerable attention. The primary purpose of this paper is to give basic properties of diamond-$\alpha$ derivatives which are a linear combination of…

经典分析与常微分方程 · 数学 2008-08-27 Moulay Rchid Sidi Ammi , Rui A. C. Ferreira , Delfim F. M. Torres

The discrete, the quantum, and the continuous calculus of variations, have been recently unified and extended by using the theory of time scales. Such unification and extension is, however, not unique, and two approaches are followed in the…

最优化与控制 · 数学 2011-09-30 Delfim F. M. Torres

The discrete-time, the quantum, and the continuous calculus of variations have been recently unified and extended. Two approaches are followed in the literature: one dealing with minimization of delta integrals; the other dealing with…

最优化与控制 · 数学 2010-05-25 Agnieszka B. Malinowska , Delfim F. M. Torres

We introduce the diamond-alpha exponential function on time scales. As particular cases, one gets both delta and nabla exponential functions. A method of solution of a homogenous linear dynamic diamond-alpha equation on a regular time scale…

经典分析与常微分方程 · 数学 2009-02-16 Dorota Mozyrska , Delfim F. M. Torres

We consider a general problem of the calculus of variations on time scales with a cost functional that is the composition of a certain scalar function with delta and nabla integrals of a vector valued field. Euler-Lagrange delta-nabla…

最优化与控制 · 数学 2015-09-15 Monika Dryl , Delfim F. M. Torres

In this paper, we investigate the monotonicity of the functions $t \mapsto \frac{\sum_{k=0}^\infty a_k w_k(t)}{\sum_{k=0}^\infty b_k w_k(t)}$ and $x \mapsto \frac{\int_\alpha^\beta f(t) w(t,x) \textrm{d} t}{\int_\alpha^\beta g(t) w(t,x)…

综合数学 · 数学 2023-06-09 Zhong-Xuan Mao , Jing-Feng Tian

We develop the calculus of variations on time scales for a functional that is the composition of a certain scalar function with the delta and nabla integrals of a vector valued field. Euler-Lagrange equations, transversality conditions, and…

最优化与控制 · 数学 2013-06-13 Monika Dryl , Delfim F. M. Torres

Dynamical studies of MHD turbulence on the one hand, and arguments based upon magnetic helicity on the other, have yielded seemingly contradictory estimates for the $\alpha$ parameter in turbulent dynamo theory. Here we show, with direct…

天体物理学 · 物理学 2007-05-23 Hongsong Chou , George B. Field

In this paper, we present some monotonicity rules for the ratio of two power series $x\mapsto \sum_{k=0}^\infty a_k x^k / \sum_{k=0}^\infty b_k x^k$ under the assumption that the monotonicity of the sequence ${a_k/b_k}$ changes twice.…

经典分析与常微分方程 · 数学 2024-04-30 Zhong-Xuan Mao , Jing-Feng Tian

In this work we propose a new and more general approach to the calculus of variations on time scales that allows to obtain, as particular cases, both delta and nabla results. More precisely, we pose the problem of minimizing or maximizing…

最优化与控制 · 数学 2010-08-30 Ewa Girejko , Agnieszka B. Malinowska , Delfim F. M. Torres

In this note we show how one can obtain results from the nabla calculus from results on the delta calculus and vice versa via a duality argument. We provide applications of the main results to the calculus of variations on time scales.

最优化与控制 · 数学 2010-01-17 M. Cristina Caputo

We introduce a fractional calculus on time scales using the theory of delta (or nabla) dynamic equations. The basic notions of fractional order integral and fractional order derivative on an arbitrary time scale are proposed, using the…

经典分析与常微分方程 · 数学 2010-12-08 Nuno R. O. Bastos , Dorota Mozyrska , Delfim F. M. Torres

We define a symmetric derivative on an arbitrary nonempty closed subset of the real numbers and derive some of its properties. It is shown that real-valued functions defined on time scales that are neither delta nor nabla differentiable can…

经典分析与常微分方程 · 数学 2012-10-24 Artur M. C. Brito da Cruz , Natalia Martins , Delfim F. M. Torres

Coherence is the most fundamental quantum feature of the nonclassical systems. The understanding of coherence within the resource theory has been attracting increasing interest among which the quantification of coherence is an essential…

量子物理 · 物理学 2018-01-16 Haiqing Zhao , Chang-shui Yu

The method of monotonization of difference schemes is being considered in the paper. The method was earlier proposed by the author for stationary problems. It is investigated in the paper more profoundly. The idea of the method is to build…

数值分析 · 计算机科学 2014-03-13 Y. V. Troshchiev

The problem of existence of solutions to nabla differential equations and nabla differential inclusions on time scales is considered. Under a special form of the set-valued constraint map, sufficient conditions for the existence of at least…

经典分析与常微分方程 · 数学 2012-07-23 Ewa Girejko , Delfim F. M. Torres
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