In this work, the authors consider the boundary value problem { y + a(t)y = g(t) f (y), 0 ≤ t ≤ 2π, y(0) = y(2π), y(0) = y(2π), and establish the existence of nonnegative solutions in the case where… (More)

The authors consider the boundary value problem { y′′ − ρ2y + λg(t)f (y) = 0, 0 t 2π, y(0) = y(2π), y′(0) = y′(2π). Under different combinations of superlinearity and sublinearity of the function f ,… (More)

In this paper, the authors consider a nonlinear fractional boundary value problem defined on a star graph. By using a transformation, an equivalent system of fractional boundary value problems with… (More)

Sufficient conditions are given for the existence of multiple solutions to a periodic boundary value problem for a fourth order nonlinear difference equation. The analysis makes use of variational… (More)

The authors consider a nonlinear fractional boundary value problem with the Dirichlet boundary condition. An associated Green’s function is constructed as a series of functions by applying spectral… (More)