scholarly journals OSCILLATIONS IN CERTAIN DIFFERENCE EQUATIONS

1997 ◽  
Vol 27 (3) ◽  
pp. 257-265
Author(s):  
ZDZISLAW SZAFRANSKI ◽  
BLAZEJ SZMANDA

We obtain sufficient conditions for the oscillation of all solutions of some linear difference equations with variable coefficients.

In this paper, the authors obtained some new sufficient conditions for the oscillation of all solutions of the fourth order nonlinear difference equation of the form ( ) ( 1 ) 0 3  anxn  pnxn  qn f xn  n = 0,1,2, … ., where an, pn, qn positive sequences. The established results extend, unify and improve some of the results reported in the literature. Examples are provided to illustrate the main result.


1991 ◽  
Vol 4 (3) ◽  
pp. 241-257 ◽  
Author(s):  
Ch. G. Philos ◽  
I. K. Purnaras

A class of linear difference equations with variable coefficients is considered. Sufficient conditions and necessary conditions for the oscillation of the solutions are established. In the special cases where the coefficients are constant or periodic the conditions become both necessary and sufficient.


2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
G. E. Chatzarakis ◽  
H. Péics ◽  
I. P. Stavroulakis

New sufficient conditions for the oscillation of all solutions of difference equations with several deviating arguments and variable coefficients are presented. Examples illustrating the results are also given.


2012 ◽  
Vol 43 (4) ◽  
pp. 491-498
Author(s):  
Mohammed Ali Jaffer I. ◽  
Selvaraj B.

In this paper some sufficient conditions for oscillation of all solutions of certain difference equations are obtained. Examples are given to illustrate the results.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Tuğba Yalçın Uzun

AbstractIn this paper, we study the oscillation behavior for higher order nonlinear Hilfer fractional difference equations of the type $$\begin{aligned}& \Delta _{a}^{\alpha ,\beta }y(x)+f_{1} \bigl(x,y(x+\alpha ) \bigr) =\omega (x)+f_{2} \bigl(x,y(x+ \alpha ) \bigr),\quad x\in \mathbb{N}_{a+n-\alpha }, \\& \Delta _{a}^{k-(n-\gamma )}y(x) \big|_{x=a+n-\gamma } = y_{k}, \quad k= 0,1,\ldots,n, \end{aligned}$$ Δ a α , β y ( x ) + f 1 ( x , y ( x + α ) ) = ω ( x ) + f 2 ( x , y ( x + α ) ) , x ∈ N a + n − α , Δ a k − ( n − γ ) y ( x ) | x = a + n − γ = y k , k = 0 , 1 , … , n , where $\lceil \alpha \rceil =n$ ⌈ α ⌉ = n , $n\in \mathbb{N}_{0}$ n ∈ N 0 and $0\leq \beta \leq 1$ 0 ≤ β ≤ 1 . We introduce some sufficient conditions for all solutions and give an illustrative example for our results.


1998 ◽  
Vol 41 (1) ◽  
pp. 49-64
Author(s):  
K. J. Harrison ◽  
J. A. Ward ◽  
L-J. Eaton

AbstractWe study the stability of linear filters associated with certain types of linear difference equations with variable coefficients. We show that stability is determined by the locations of the poles of a rational transfer function relative to the spectrum of an associated weighted shift operator. The known theory for filters associated with constant-coefficient difference equations is a special case.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Kirill M. Chudinov

Abstract We consider explicit sufficient conditions for all solutions of a first-order linear difference equation with several variable delays and non-negative coefficients to be oscillatory. The conditions have the form of inequalities bounding below the upper and lower limits of the sums of coefficients over a subset of the discrete semiaxis. Our main results are oscillation tests based on a new principle for composing the estimated sums of coefficients. We also give some results in the form of examples, including a counterexample to a wrong oscillation test cited in several recent papers.


2021 ◽  
Vol 21 (1) ◽  
pp. 145-162
Author(s):  
MERVE KARA ◽  
YASIN YAZLIK

In this paper, we show that the system of difference equations can be solved in the closed form. Also, we determine the forbidden set of the initial values by using the obtained formulas. Finally, we obtain periodic solutions of aforementioned system.


2018 ◽  
Vol 68 (5) ◽  
pp. 1083-1096 ◽  
Author(s):  
George E. Chatzarakis ◽  
Lana Horvat Dmitrović ◽  
Mervan Pašić

AbstractThe purpose of this paper is to derive sufficient conditions for the oscillation of all solutions of a difference equation with several non-monotone deviating arguments and nonnegative coefficients. Corresponding difference equations of both retarded and advanced type are studied. Examples illustrating the significance of the results are also given.


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