Existence of positive solutions for nnth-order pp-Laplacian singular sublinear boundary value problems

This paper investigates the existence of positive solutions for nnth-order (n≥3n≥3) pp-Laplacian singular sub-linear boundary value problems. A necessary and sufficient condition for the existence of Spn−1 positive solutions is given by constructing lower and upper solutions and with the comparison theorem. Our nonlinearity f(t,x1,x2,…,xn−1)f(t,x1,x2,…,xn−1) may be singular at xi=0,i=1,2,…,n−1,t=0 and/or t=1t=1.