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Oscillatory properties of second order half-linear difference equations

Pavel Řehák (2001)

Czechoslovak Mathematical Journal

We study oscillatory properties of the second order half-linear difference equation Δ ( r k | Δ y k | α - 2 Δ y k ) - p k | y k + 1 | α - 2 y k + 1 = 0 , α > 1 . ( HL ) It will be shown that the basic facts of oscillation theory for this equation are essentially the same as those for the linear equation Δ ( r k Δ y k ) - p k y k + 1 = 0 . We present here the Picone type identity, Reid Roundabout Theorem and Sturmian theory for equation (HL). Some oscillation criteria are also given.

Oscillatory properties of third-order semi-noncanonical nonlinear delay difference equations

Govindasamy Ayyappan, George E. Chatzarakis, Thaniarasu Kumar, Ethiraj Thandapani (2023)

Mathematica Bohemica

We study the oscillatory properties of the solutions of the third-order nonlinear semi-noncanonical delay difference equation D 3 y ( n ) + f ( n ) y β ( σ ( n ) ) = 0 , where D 3 y ( n ) = Δ ( b ( n ) Δ ( a ( n ) ( Δ y ( n ) ) α ) ) is studied. The main idea is to transform the semi-noncanonical operator into canonical form. Then we obtain new oscillation theorems for the studied equation. Examples are provided to illustrate the importance of the main results.

Partial generalized synchronization theorems of differential and discrete systems

Jianyi Jing, Lequan Min, Geng Zhao (2008)

Kybernetika

This paper presents two theorems for designing controllers to achieve directional partial generalized synchronization (PGS) of two independent (chaotic) differential equation systems or two independent (chaotic) discrete systems. Two numerical simulation examples are given to illustrate the effectiveness of the proposed theorems. It can be expected that these theorems provide new tools for understanding and studying PGS phenomena and information encryption.

Plus-operators in Krein spaces and dichotomous behavior of irreversible dynamical systems with discrete time

V. Khatskevich, L. Zelenko (2006)

Studia Mathematica

We study dichotomous behavior of solutions to a non-autonomous linear difference equation in a Hilbert space. The evolution operator of this equation is not continuously invertible and the corresponding unstable subspace is of infinite dimension in general. We formulate a condition ensuring the dichotomy in terms of a sequence of indefinite metrics in the Hilbert space. We also construct an example of a difference equation in which dichotomous behavior of solutions is not compatible with the signature...

Positive fixed point theorems arising from seeking steady states of neural networks

Gen Qiang Wang, Sui-Sun Cheng (2010)

Mathematica Bohemica

Biological systems are able to switch their neural systems into inhibitory states and it is therefore important to build mathematical models that can explain such phenomena. If we interpret such inhibitory modes as `positive' or `negative' steady states of neural networks, then we will need to find the corresponding fixed points. This paper shows positive fixed point theorems for a particular class of cellular neural networks whose neuron units are placed at the vertices of a regular polygon. The...

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