Nonexistence of positive solutions of quasilinear differential equations

Consider the following quasilinear differential equation: (¦u′(t)¦p−2 u′(t))′ + f(t, u(t)) = 0, a < t < b, p > 1, (E) subject to one of the following boundary conditions: u(a) = u(b) = 0, (BC1) u(a) = u′(b) = 0, (BC2) u′(a) = u(b) = 0. (BC3) Under suitable conditions on f(t,u), we obtain the nonexistence of solutions of (E) with respect to (BCi), i = 1, 2, 3.