Forced oscillation of sublinear impulsive differential equations via nonprincipal solution

In this paper, we give new oscillation criteria for forced sublinear impulsive differential equations of the form( r ( t ) x ′ ) ′ + q ( t ) | x | γ − 1 x = f ( t ) , t ≠ θ i ;Δ r ( t ) x ′ + q i | x | γ − 1 x = f i ,t = θ i ,where γ ∈(0,1), under the assumption that associated homogenous linear equation( r ( t ) z ′ ) ′ + q ( t ) z = 0 , t ≠ θ i ;Δ r ( t ) z ′ + q i z = 0 , t = θ iis nonoscillatory.