Agarwal, R. P., Grace, S. R. and O’Regan, D. , Oscillation Theory of Second Order Linear, Half-Linear, Superlinear and Sublinear Dynamic Equations , Kluwer Academic Publishers, Dordrecht

Agarwal, R. P., Grace, S. R. and O’Regan, D. , Oscillation Theory for Second Order Linear, Half-Linear, Superlinear and Sublinear Dynamic Equations , Kluwer Academic Publishers (Dordrecht

ELBERT, Á A., half-linear second order differential equation, Qualitative theory of differential equations (Szeged, 1979), Colloq. Math. Soc. János Bolyai , 30 , North-Holland, Amsterdam - New York, 1981, 153

Agarwal , R.P., Grace , A.R. and O’Regan , D., Oscillation theory for second order linear, half-linear, superlinear and sublinear dynamic equations , Kluwer Academic Publishers, Dordrecht, 2002

. , Oscillation theory for second order linear, half-linear, superlinear and sublinear dynamic equations , Kluwer Academic Publishers, Dordrecht, 2002 . [2] A mmann , K. and T eschl

## Abstract

We consider a nonoscillatory half-linear second order differential equation

*h*. Using this solution we construct a function

*d*such that the equation

## Summary

We establish new comparison theorems on the oscillation of solutions of a class of perturbed half-linear differential equations.
These improve the work of Elbert and Schneider [6] in which connections are found between half-linear differential equations
and linear differential equations. Our comparison theorems are not of Sturm type or Hille--Wintner type which are very famous.
We can apply the main results in combination with Sturm's or Hille--Wintner's comparison theorem to a half-linear differential
equation of the general form (|x'|^{α-1}x')' + a(t) |x|^{α-1}x = 0.

## Abstract

Several comparison theorems with respect to powers in nonlinearities for half-linear differential equations are presented. The Riccati transformation and the reciprocity principle are utilized. Some examples and an integral extension of the classical comparison result are presented as well.

## Abstract

We consider half-linear retarded functional differential equations of the form

## Abstract

This paper deals with the second-order half-linear differential equation

*ϕ*

_{p}(

*z*):= |

*z*|

^{p−2}

*z*is the so-called one-dimensional

*p*-Laplacian operator. Our main purpose is to establish new criteria for all nontrivial solutions to be oscillatory and for those to be nonoscillatory. In our theorems, the parametric curve given by (

*a*(

*t*),

*b*(

*t*)) plays a critical role in judging whether all solutions are oscillatory or nonoscillatory. This paper takes a di-erent approach from most of the previous research. Our results are new even in the linear case (

*p*= 2). The method used here is mainly phase plane analysis for a system equivalent to the half-linear differential equation. Some suitable examples are included to illustrate the main results. Global phase portraits are also attached.