*Correspondence: [email protected] Institute of Applied Physics and Computational Mathematics, Beijing, 100088, P.R. China College of Mathematics, Jilin University, Changchun, 130012, P.R. China Abstract In this paper, we establish the Nagumo theorems for boundary value problems associated with a class of third-order singular nonlinear equations: (p(t)x′)′′ = f (t, x,p(t)x′, (p(t)x′)′), ∀t ...

The singular nonlinear three-point boundary value problems { −(Lu)(t) = h(t)f (u(t)), 0 < t < 1, βu(0)− γ u′(0) = 0, u(1) = αu(η) are discussed under some conditions concerning the first eigenvalue corresponding to the relevant linear operator, where (Lu)(t) = (p(t)u′(t))′+q(t)u(t), 0 < η < 1, h(t) is allowed to be singular at both t = 0 and t = 1, and f need not be nonnegative. The associated ...