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1

Point process of clusters for a stationary Gaussian random field on a lattice

Lu Yingyin, Guo Jinhui

Probability and Mathematical Statistics

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2023

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Vol. 43, Fasc. 2

247--262

EN

It is well established that the normalized exceedances resulting from a standard stationary Gaussian triangular array at high levels follow a Poisson process under the Berman condition. To model frequent cluster phenomena, we consider the asymptotic distribution of the point process of clusters for a Gaussian random field on a lattice. Our analysis demonstrates that the point process of clusters also converges to a Poisson process in distribution, provided that the correlations of the Gaussian random field meet certain conditions. Additionally, we provide a numerical example to illustrate our theoretical results.

2

Existence and asymptotic behavior of nonoscillatory solutions of half-linear ordinary differential equations

Naito Manabu

Opuscula Mathematica

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2023

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Vol. 43, no. 2

221--246

EN

We consider the half-linear differential equation (|x′|αsgn x′)′ + q(t)|x|αsgn x = 0, t ≥ t0, under the condition [formula] It is shown that if certain additional conditions are satisfied, then the above equation has a pair of nonoscillatory solutions with specific asymptotic behavior as t → ∞.

3

Asymptotic behavior of solutions toward the constant state to the Cauchy problem for the non-viscous diffusive dispersive conservation law

Yoshida Natsumi

Journal of Applied Analysis

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2023

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Vol. 29, nr 2

251--259

EN

In this paper, we investigate the asymptotic behavior of solutions to the Cauchy problem for the scalar non-viscous diffusive dispersive conservation law where the far field constant state is prescribed. We prove that the solution of the Cauchy problem tends toward the constant state as time goes to infinity.

4

Forced oscillation and asymptotic behavior of solutions of linear differential equations of second order

Shoukaku Yutaka

Opuscula Mathematica

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2022

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Vol. 42, no. 6

867--885

EN

The paper deals with the second order nonhomogeneous linear differential equation (p(t)y′(t))′ + q(t)y(t) = f(t), which is oscillatory under the assumption that p(t) and q(t) are positive, continuously differentiable and monotone functions on [0,∞). Throughout this paper we shall use pairs of quadratic forms, which obtained by different methods than Kusano and Yoshida. This form will lead to a property of qualitative behavior, including amplitudes and slopes, of oscillatory solutions of the above equation. In addition, we will discuss the existence of three types (moderately bounded, small, large) of oscillatory solutions, which are based on results due to Kusano and Yoshida.

5

Asymptotic behavior of solution of Whitham-Broer-Kaup type equations with negative dispersion

Bedjaoui Nabil, Kumar Rajesh, Mammeri Youcef

Journal of Applied Analysis

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2022

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Vol. 28, nr 1

109--119

EN

In this work, we discuss the long time behavior of solutions of the Whitham-Broer-Kaup system with Lipschitz nonlinearity and negative dispersion term. We prove the global well-posedness when α + β2 < 0 as well as the convergence to 0 of small solutions at rate O(t−1/2).

6

Source term model for elasticity system with nonlinear dissipative term in a thin domain

Dilmi Mohamed, Dilmi Mourad, Boulaaras Salah, Benseridi Hamid

Demonstratio Mathematica

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2022

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Vol. 55, nr 1

437--451

EN

This article establishes an asymptotic behavior for the elasticity systems with nonlinear source and dissipative terms in a three-dimensional thin domain, which generalizes some previous works. We consider the limit when the thickness tends to zero, and we prove that the limit solution u∗ is a solution of a two-dimensional boundary value problem with lower Tresca’s free-boundary conditions. Moreover, we obtain the weak Reynolds-type equation.

7

Remarks on the existence of nonoscillatory solutions of half-linear ordinary differential equations, I

Naito Manabu

Opuscula Mathematica

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2021

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Vol. 41, no. 1

71--94

EN

We consider the half-linear differential equation of the form [formula], under the assumption [formula]. It is shown that if a certain condition is satisfied, then the above equation has a pair of nonoscillatory solutions with specific asymptotic behavior as t →∞.

8

Oscillation criteria for even order neutral difference equations

Selvarangam S., Rupadevi S. A., Thandapani E., Pinelas S.

Opuscula Mathematica

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2019

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Vol. 39, no. 1

91--108

EN

In this paper, we present some new sufficient conditions for oscillation of even order nonlinear neutral difference equation of the form [formula] where m ≥ 2 is an even integer, using arithmetic-geometric mean inequality. Examples are provided to illustrate the main results.

9

Nonhomogeneous nonlinear oscillator with damping: asymptotic analysis in continuous and discrete time

Rouhani Behzad Djafari, Piranfar Mohsen Rahimi

Demonstratio Mathematica

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2019

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Vol. 52, nr 1

274--282

EN

We consider the following second order evolution equation modelling a nonlinear oscillator with damping ü(t) +𝛾 ů(t) + Au(t) = f(t), where A is a maximal monotone andα-inverse strongly monotone operator in a real Hilbert space H. With suitable assumptions on 𝛾 and f(t) we show that A-1(0) ≠ ∅, if and only if (SEE) has a bounded solution and in this case we provide approximation results for elements of A-1(0) by proving weak and strong convergence theorems for solutions to (SEE) showing that the limit belongs to A-1(0). As a discrete version of (SEE), we consider the following second order difference equation un+1-un-αn(un-un-1)+λnAun+1 ∋ f(t), where A is assumed to be only maximal monotone (possibly multivalued). By using the results in [Djafari Rouhani B., Khatibzadeh H., On the proximal point algorithm, J. Optim. Theory Appl., 2008, 137, 411-417], we prove ergodic, weak and strong convergence theorems for the sequence un, and show that the limit is the asymptotic center of un and belongs to A−1(0). This again shows that A−1(0) ≠ ∅ if and only if un is bounded. Also these results solve an open problem raised in [Alvarez F., Attouch H., An inertial proximal method for maximal monotone operators via dicretization of a nonlinear oscillator with damping, Set Valued Anal., 2001, 9, 3-11], namely the study of the convergence results for the inexact inertial proximal algorithm. Our paper is motivated by the previous results in [Djafari Rouhani B., Asymptotic behaviour of quasi-autonomous dissipative systems in Hilbert spaces, J. Math. Anal. Appl., 1990, 147, 465-476; Djafari Rouhani B., Asymptotic behaviour of almost nonexpansive sequences in a Hilbert space, J. Math. Anal. Appl., 1990, 151, 226–235; Djafari Rouhani B., Khatibzadeh H., Asymptotic behavior of bounded solutions to some second order evolution systems, Rocky Mountain J. Math., 2010, 40, 1289-1311; Djafari Rouhani B., Khatibzadeh H., A strong convergence theorem for solutions to a nonhomogeneous second order evolution equation, J. Math. Anal. Appl., 2010, 363, 648-654; Djafari Rouhani B., Khatibzadeh H., Asymptotic behavior of bounded solutions to a class of second order nonhomogeneous evolution equations, Nonlinear Anal., 2009, 70, 4369-4376; Djafari Rouhani B., Khatibzadeh H., On the proximal point algorithm, J. Optim. Theory Appl., 2008, 137, 411-417] and significantly improves upon the results of [Attouch H., Maingé P. E., Asymptotic behavior of second-order dissipative evolution equations combining potential with non-potential effects, ESAIM Control Optim. Calc. Var., 2011, 17(3), 836-857], and [Alvarez F., Attouch H., An inertial proximal method for maximal monotone operators via dicretization of a nonlinear oscillator with damping, Set Valued Anal., 2001, 9, 3-11].

10

Asymptotic profiles for a class of perturbed burgers equations in one space dimension

Dkhil F., Hamza M. A., Mannoubi B.

Opuscula Mathematica

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2018

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Vol. 38, no. 1

41--80

EN

In this article we consider the Burgers equation with some class of perturbations in one space dimension. Using various energy lunctionals in appropriate weighted Sobolev spaces rewritten in the variables [formula] and log τ, we prove that the large time behavior of solutions is given by the sell-similar solutions ol the associated Burgers equation.

11

Oscillatory behavior of higher order nonlinear homogeneous neutral delay dynamic equations with positive and negative coefficients

Panigrahi S., Reddy P. R.

Journal of Applied Analysis

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2018

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Vol. 24, nr 2

139--154

EN

In this paper, we derive some sufficient conditions for the oscillatory and asymptotic behavior of solutions of the higher order nonlinear neutral delay dynamic equation with positive and negative coefficients. The results of this paper extend and generalize the results of [S. Panigrahi and P. Rami Reddy, Oscillatory and asymptotic behavior of fourth order non-linear neutral delay dynamic equations, Dyn. Contin. Discrete Impuls. Syst. Ser. AMath. Anal. 20 (2013), 143-163] and [S. Panigrahi, J. R. Graef and P. Rami Reddy, Oscillation results for fourth order nonlinear neutral dynamic equations, Commun. Math. Anal. 15 (2013), 11-28]. Examples are included to illustrate the validation of the results.

12

Oscillatory and asymptotic behavior of a third-order nonlinear neutral differential equation

Graef J. R., Tunc E., Grace S. R.

Opuscula Mathematica

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2017

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Vol. 37, no. 6

839--852

EN

This paper discusses oscillatory and asymptotic properties of solutions of a class of third-order nonlinear neutral differential equations. Some new sufficient conditions for a solution of the equation to be either oscillatory or to converges to zero are presented. The results obtained can easily be extended to more general neutral differential equations as well as to neutral dynamic equations on time scales. Two examples are provided to illustrate the results.

13

Existence and asymptotic behavior of positive solutions of a semilinear elliptic system in a bounded domain

Chaieb M., Dhifli A., Zermani S.

Opuscula Mathematica

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2016

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Vol. 36, no. 3

315--336

EN

Let Ω be a bounded domain in [formula] with a smooth boundary [formula]. We discuss in this paper the existence and the asymptotic behavior of positive solutions of the following semilinear elliptic system [formula] Here r, s ∈ R, α, β < 1 such that γ := (1 - α) (1 - β ) - rs > 0 and the functions [formula] are nonnegative and satisfy some appropriate conditions with reference to Karamata regular variation theory.

14

Strongly increasing solutions of cyclic systems of second order differential equations with power-type nonlinearities

Jaroś J., Takaśi K.

Opuscula Mathematica

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2015

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Vol. 35, no. 1

47--69

EN

We consider n-dimensional cyclic systems of second order differential equations [formula] (*) under the assumption that the positive constants α and β satisfy α1...αn > β1...βn and pi(t) and qi(t) are regularly varying functions, and analyze positive strongly increasing solutions of system (*) in the framework of regular variation. We show that the situation for the existence of regularly varying solutions of positive indices for (*) can be characterized completely, and moreover that the asymptotic behavior of such solutions is governed by the unique formula describing their order of growth precisely. We give examples demonstrating that the main results for (*) can be applied to some classes of partial differential equations with radial symmetry to acquire accurate information about the existence and the asymptotic behavior of their radial positive strongly increasing solutions.

15

Spectra of some selfadjoint Jacobi operators in the double root case

Motyka W.

Opuscula Mathematica

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2015

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Vol. 35, no. 3

353--370

EN

In this paper we prove a mixed spectrum of Jacobi operators defined by λn = s(n)(1 + x(n)) and qn = — 2s(n)(l+y/(n)), where (s(n)) is a real unbounded sequence, (x(n)) and (y(n)) are some perturbations.

16

Positive solutions with specific asymptotic behavior for a polyharmonic problem on Rn

Dhifli A.

Opuscula Mathematica

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2015

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Vol. 35, no. 1

5--19

EN

This paper is concerned with positive solutions of the semilinear polyharmonic equation [formula] on Rn, where m and n are positive integers with n > 2m, α ∈ e (—1,1). The coefncient a is assumed to satisfy[formula], where Λ ∈ (2m,∞) and [formula]is positive with [formula], one also assumes that [formula]. We prove the existence of a positive solution u such that [formula], with [formula] and a function L, given explicitly in terms of L and satisfying the same condition as infinity. (Given positive functions ∫ and g on Rn, ∫≈ g means that [formula]for some constant c > 1.)

17

Asymptotic behavior of positive solutions of a semilinear Dirichlet problem in the annulus

Dridi S., Khamessi B.

Opuscula Mathematica

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2015

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Vol. 35, no. 1

21--36

EN

In this paper, we establish existence and asymptotic behavior of a positive classical solution to the following semilinear boundary value problem: [formula] Here O is an annulus in [formula] and q is a positive function in [formula], satisfying some appropriate assumptions related to Karamata regular variation theory. Our arguments combine a method of sub- and supersolutions with Karamata regular variation theory.

18

Dynamic balance research of protected systems

Naumeyko I., Alja'afreh M.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2015

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Vol. 4, No 3

85-90

EN

The dynamic models of the complex ergatic objects' behavior, presented in the form of differentia equations and their systems were studied. The stability and other properties are researched. The methods of analysis and reduce of harmful factors and their impact on people were theoretically proved. The methods of analysis and critical points removal in dynamic models of hazards distribution are offered. The object of study is the system of the harmful external factors protection. Subject of research is the system of two nonlinear differential equations as a model of technical systems with protection. The object of protection is described by logistic equation. and defense system - by non-linear differential equation with a security functions of rather general form. This paper describes critical modes analysis and stationary states’ stability of protected systems with harmful influences. Numerical solution of general problem and also the analytical solution for the case of fixed expected harmful effects have been obtained. Various types of general models for "Man-machine-environment" systems were studied. Each of describes some kind of the practically important quality of object in an appropriate way. And All together they describe the object in terms of it’s safe operation. Their further detailing process results to either well-known, or some new subsystems’ models. Systems with "fast" protection at a relatively slow dynamics of the object were studied. This leads to the models with small parameter and asymptotic solutions of differentia equations. Some estimates for protection cost in different price-functional and for different functions in the right part of equation, which describes the dynamics of defense were obtained. For calculations, analysis and graphical representations some of mathematical packages was applied.

19

On the asymptotic behavior of solutions to nonlinear differential equations of the second order

Tunç C., Ayhan T.

Commentationes Mathematicae

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2015

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Vol 55, No. 1

1--8

EN

We study the asymptotic behavior of solutions to a nonlinear differential equation of the second order whose coefficient of nonlinearity is a bounded function for arbitrarily large values of x in R. We obtain certain sufficient conditions which guarantee boundedness of solutions, their convergence to zero as x→∞ and their unboundedness

20

Oscillatory and asymptotic behavior of fourth order nonlinear neutral delay differential equations with positive and negative coefficients

Tripathy A. K., Panigrahi S, Basu R

Fasciculi Mathematici

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2014

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Nr 52

155--174

EN

In this paper, Oscillatory and asymptotic behaviour of solutions of a class of nonlinear fourth order neutral differential equations with positive and negative coefficients of the form (H) (r(t)(y(t) + p(t)y(t - τ))")" + q(t)G(y(t - α)) - h(t) H (y(t - β)) = 0 and (NH) (H) (r(t)(y(t) + p(t)y(t - τ))")" + q(t)G(y(t - α)) - h(t) H (y(t - β)) =f (t) are studied under the assumption ...[wzór] for various ranges of p(t). Using Schauder’s fixed point theorem, sufficient conditions are obtained for the existence of bounded positive solutions of (NH).