Upper and lower solutions method and a superlinear singular boundary value problem
The singular boundary value problem u" + g(t, u, u') = 0, for t is an element of (0, 1), u(0) = u(1) = 0, is studied in this paper. The singularity may appear at u = 0, t = 0, and t = 1, and the function g may be superlinear at u = infinity and change sign, The existence of solutions is obtained via an upper and lower solutions method. (C) 2002 Elsevier Science Ltd. All rights reserved.
upper and lower solutions superlinear singular boundary value problem existence