Periodic solutions for p-Laplacian neutral Liénard equation with a sign-variable coefficient

Using Lu's continuation theorem, the extension one of Manásevich-Mawhin, we study the existence of periodic solutions for p-Laplacian neutral Liénard equation of the form(ϕp(x(t)-cx(t-σ))′)′+f(x(t))x′(t)+β(t)g(x(t-τ(t))=e(t).It is meaningful that the coefficient β(t) ahead of the nonlinear term g(x(t-τ(t)) is allowed to change sign in this paper, which could be achieved infrequently in corresponding papers.