In this paper, we give sufficient conditions for the existence or the nonexistence of positive solutions of the nonlinear fractional boundary value problem egin{gather*} D_{0^{+}}^{lpha}u+a(t)f(u(t))=0, 0展开▼
机译：在本文中，我们为非线性分数阶边值问题 begin {gather *} D_ {0 ^ {+}} ^ { alpha} u + a（t）f的正解的存在或不存在提供了充分的条件（u（t））= 0，0 展开▼
