الفهرس | Only 14 pages are availabe for public view |
Abstract This thesis contains four chapters: Chapter 1 contains the basic concepts of the theory of functional differential equations and some preliminary results of the theory of second order neutral delay differential equations. In Chapter 2, we give an introduction to the theory of dynamic equations on time scales, differentiation and integration on arbitrary time scale. Additionally, the most important studies for the oscillation theory of second order neutral delay dynamic equations on time scales are presented. In Chapter 3, we establish some new oscillation criteria for the second-order nonlinear functional dynamic equation with neutral term (r(t)((m(t)y(t) + p(t)y(τ (t)))^Δ )^γ )^Δ + f(t,y(δ(t))) = 0; on a time scale T by using the generalized Riccati technique. The present results not only improve, generalize and extend some of the previous results [21, 27, 39, 45, 48] but also can be applied to some oscillation problems that are not covered before. At the end of this Chapter, a counter example is given to illustrate the main theorem of E. Thandapani et al. [41]. The correct formula for this theorem and related results in their work are given. The results of this chapter are published (see [4] and [5]). In Chapter 4, we introduce some new oscillation criteria for the second-order nonlinear functional dynamic equation with non positive neutral term (r(t)((m(t)y(t) - p(t)y(τ (t)))^Δ )^γ )^Δ+ f(t,y(τ(t))) = 0; t ∈ T on a time scale T: The current results not only improve and extend results of [8, 32], but also can be applied to some oscillation problems that are not covered before. The results of this chapter are submitted . |