The oscillation and nonoscillation of the advanced differential equations x′(t)−p(t)x(t+τ)=0, t⩾t0(∗) and x′(t)−∑i=1npi(t)x(t+τi)=0, t⩾t0(∗∗) are investigated, where p(t),pi(t)∈C([t0,∞),[0,∞)), τ and τi are positive constants. At first, a sharp sufficient condition for the oscillation of Eq. (∗) is obtained, then the result is generalized to Eq. (∗∗). These results improve the corresponding conclusions derived by Ladas and Stavroulakis (J. Differential Equations 44 (1982) 134–152). Next, two examples are given to illustrate...
