In this paper, new concepts which are called: left derivations and generalized left derivations in nearrings have been defined. Furthermore, the commutativity of the 3-prime near-ring which involves some
algebraic identities on generalized left derivation has been studied.

Let R be a prime ring and δ a right (σ,τ)-derivation on R. In the present paper we will prove the following results:
First, suppose that R is a prime ring and I a non-zero ideal of R if δ acts as a homomorphism on I then δ=0 on R, and if δ acts an anti- homomorphism on I then either δ=0 on R or R is commutative.
Second, suppose that R is 2-torsion-free prime ring and J a non-zero Jordan ideal and a subring of R, if δ acts as a homomorphism on J then δ=0 on J, and if δ acts an anti- homomorphism on J then either δ=0 on J or J
Z(R).

The purpose of this paper is to study the instability of the zero solution of some type of nonlinear delay differential equations of fourth order by using the Lyapunov-Krasovskii functional approach; we obtain some conditions of instability of solution of such equation.

The purpose of this paper is to study the instability of the zero solution of some type of nonlinear delay differential equations of fifth order with delay by using the Lyapunov-Krasovskii functional approach, we obtain some conditions of instability of solution of such equation.

We present the concept of maps Γ- periodi2 on Γ -near-ring S. Our main goal is to research and explore the presence and mapping traits such as h Γ –hom anti-Γ –hom, Γ –α-derivations of Γ -periodi2 on Γ- near-rings.

In this paper, we investigate prime near – rings with two sided α-n-derivations
satisfying certain differential identities. Consequently, some well-known results
have been generalized. Moreover, an example proving the necessity of the primness
hypothesis is given.

This paper is illustrates the sufficient conditions of the uniformly asymptotically stable and the bounded of the zero solution of fifth order nonlinear differential equation with a variable delay τ(t)