arXiv subjects
Publications and source records attributed to Basak Karpuz.
We provide explicit conditions for uniform stability, global asymptotic stability and uniform exponential stability for dynamic equations with a single delay and a nonnegative coefficient. Some examples on nonstandard time scales are also given to show applicability and sharpness of the new results.
In [Bull. Acad. Polon. Sci. Sér. Sci. Math. 29 (1981), no.~7-8, 367--370], Philos proved the following result: Let $f:[t_{0},\infty)_{\mathbb{R}}\to\mathbb{R}$ be an $n$-times differentiable function such that $f^{(n)}(t)\leq0$ ($\not\equiv0$) and $f(t)>0$ for all $t\geq{}t_{0}$. If $f$ is unbounded, then $f(t)\geq\frac{λt^{n-1}}{(n-1)!}f^{(n-1)}(t)$ for all sufficiently large $t$, where $λ\in(0,1)_{\mathbb{R}}$. In this work, we first present time scales unification of this result. Then, by using it, we provide sufficient conditions for oscillation and asymptotic behaviour of solutions to higher-order neutral dynamic equations.
This paper studies existence and uniqueness of solutions to generalized Volterra integral equations. Since our proof for existence and uniqueness does not make use of Banach fixed point theorem unlike the previous papers focused on this subject, we can replace continuity property of the kernel function with the weaker one rd-continuity. The paper also covers results concerning the following concepts: The notion of resolvent kernel, and its role in formulation of the solution, the reciprocity property of kernels, Piccard iterates, relation between linear dynamic equations and Volterra integral equations, some special type of kernels together with several illustrative examples.
After introducing the concept of null functions, we shall present a uniqueness result in the sense of the null functions for the Laplace transform on time scales with arbitrary graininess. The result can be regarded as a dynamic extension of the well-known Lerch's theorem.
The purpose of this paper is to establish Picard-Lindelöf theorem for local uniqueness and existence results for first-order systems of nonlinear delay dynamic equations. In the linear case, we extend our results to global existence and uniqueness of solutions on the entire interval (allowed to be unbounded above), and prove the variation of parameters formula for the unique solution in terms of the principal solution. A simple example concerning the ordinary case is also provided.
In this paper, we study both the oscillation and the stability of impulsive differential equations when not only the continuous argument but also the impulse condition involves delay. The results obtained in the present paper improve and generalize the main results of the key references in this subject. An illustrative example is also provided.