A role of the coefficient of the differential term in qualitative theory of half-linear equations

summary:The aim of this contribution is to study the role of the coefficient $r$ in the qualitative theory of the equation $(r(t)\Phi (y^{\Delta}))^{\Delta} +p(t)\Phi (y^{\sigma})=0$, where $\Phi (u)=|u|^{\alpha -1}\mathop{\rm sgn}u$ with $\alpha >1$. We discuss sign and smoothness conditions posed on $r$, (non)availability of some transformations, and mainly we show how the behavior of $r$, along with the behavior of the graininess of the time scale, affect some comparison results and (non)oscillation criteria. At the same time we provide a survey of recent results acquired by sophisticated modifications of the Riccati type technique, which are supplemented by some new observations

Amended criteria of oscillation for nonlinear functional dynamic equations of second-order

In this paper, the sharp Hille-type oscillation criteria are proposed for a class of secondorder nonlinear functional dynamic equations on an arbitrary time scale, by using the technique of Riccati transformation and integral averaging method. The obtained results demonstrate an improvement in Hille-type compared with the results reported in the literature. Some examples are provided to illustrate the significance of the obtained results. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The authors would like to thank anonymous referees for their careful reading of the entire manuscript, which helped significantly improve this paper’s quality. This work was supported by Research Deanship of Hail University under grant No. 0150396

Oscillatory and Asymptotic Behavior of Nonlinear Functional Dynamic Equations of Third Order

The purpose of this work is to derive sufficient conditions for the oscillation of all solutions of the third-order functional dynamic equation p2ξφγ2p1ξφγ1yΔξΔΔ+pξφβygξ=0, on a time scale T. In addition, we present some Hille-type conditions for generalized third-order dynamic equations that improve and extend significant contributions reported in the literature without imposing time-scale restrictions. An example is given to demonstrate the essential results. © 2022 Taher S. Hassan et al

Differential/Difference Equations

The study of oscillatory phenomena is an important part of the theory of differential equations. Oscillations naturally occur in virtually every area of applied science including, e.g., mechanics, electrical, radio engineering, and vibrotechnics. This Special Issue includes 19 high-quality papers with original research results in theoretical research, and recent progress in the study of applied problems in science and technology. This Special Issue brought together mathematicians with physicists, engineers, as well as other scientists. Topics covered in this issue: Oscillation theory; Differential/difference equations; Partial differential equations; Dynamical systems; Fractional calculus; Delays; Mathematical modeling and oscillations

Differentiable positive definite kernels on two-point homogeneous spaces

In this work we study continuous kernels on compact two-point homogeneous spaces which are positive definite and zonal (isotropic). Such kernels were characterized by R. Gangolli some forty years ago and are very useful for solving scattered data interpolation problems on the spaces. In the case the space is the d-dimensional unit sphere, J. Ziegel showed in 2013 that the radial part of a continuous positive definite and zonal kernel is continuously differentiable up to order ⌊(d−1)/2⌋ in the interior of its domain. The main issue here is to obtain a similar result for all the other compact two-point homogeneous spaces.CNPq (grant 141908/2015-7)FAPESP (grant 2014/00277-5

Hille-Nehari theorems for dynamic equations with a time scale independent critical constant

In this paper, we give Hille-Nehari test for nonoscillation/oscillation of the dynamic equatio