摘要

In this paper, we establish the existence of multiple positive solutions to positone and semipositone Dirichlet-type boundary value problems of the nonlinear fractional differential equation: D(0+)(alpha) u(t) + f(t, u(t)) = 0, 0 < t < 1, u(0) = u(1) = 0 by using the Leray-Schauder nonlinear alternative and a fixed-point theorem on cones, where 1 < alpha < 2 is a real number and D(0+)(alpha) is the standard Riemann-Liouville derivative. Here our nonlinearity f may be singular at u = 0.

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