Existence of positive solutions for 2nth-order singular sublinear boundary value problems

This paper investigates the existence of positive solutions for 2nth-order (n > 1) singular sublinear boundary value problems. A necessary and sufficient condition for the existence of C2n−2[0, 1] as well as C2n−1[0, 1] positive solutions is given by constructing lower and upper solutions and with the maximal theorem. Our nonlinearity f (t,x1, x2, . . . , xn) may be singular at xi = 0, i = 1, 2, . . . , n, t = 0 and/or t = 1.  2004 Elsevier Inc. All rights reserved.