Uniqueness of positive solutions for a class of fractional boundary value problems

The work is concerned with the existence and uniqueness of positive solutions for the following fractional boundary value problem: {D0+νu(t)+h(t)f(t,u(t))=0,03n>3, and D0+ν is the standard Riemann–Liouville fractional derivative of order νν. Our main results are formulated in terms of spectral radii of some related linear integral operators, and the nonlinearity ff is considered to grow only sublinearly.