Existence of positive solutions for a class of higher-order mm-point boundary value problems

We investigate the existence of positive solutions with respect to a cone for a higher-order nonlinear differential system, subject to some boundary conditions which involve $m$ points

Existence of positive solutions for a semipositone discrete boundary value problem

We investigate the existence of positive solutions for a nonlinear second-order difference equation with a linear term and a sign-changing nonlinearity, supplemented with multi-point boundary conditions. In the proof of our main results, we use the Guo–Krasnosel'skii fixed point theorem. &nbsp

Existence of solutions for a system of fractional boundary value problems

We study the existence of solutions for a system of Riemann-Liouville fractional differential equations with nonlinearities dependent of fractional integrals, supplemented with uncoupled nonlocal boundary conditions which contain various fractional derivatives and Riemann-Stieltjes integrals. We use the fixed point theory in the proof of our main theorems

Positive solutions for a system of fractional differential equations with p-Laplacian operator and multi-point boundary conditions

We investigate the existence and nonexistence of positive solutions for a system of nonlinear Riemann–Liouville fractional differential equations with parameters and p-Laplacian operator subject to multi-point boundary conditions, which contain fractional derivatives. The proof of our main existence results is based on the Guo–Krasnosel'skii fixed-point theorem

Positive solutions for systems of second-order integral boundary value problems

We investigate the existence and nonexistence of positive solutions of a system of second-order nonlinear ordinary differential equations, subject to integral boundary conditions

Existence of positive solutions for a system of semipositone fractional boundary value problems

We investigate the existence of positive solutions for a system of nonlinear Riemann-Liouville fractional differential equations with sign-changing nonlinearities, subject to coupled integral boundary conditions

Existence of positive solutions for a singular fractional boundary value problem

We study the existence of positive solutions for a nonlinear Riemann–Liouville fractional differential equation with a sign-changing nonlinearity, subject to multi-point fractional boundary conditions

On a singular Riemann–Liouville fractional boundary value problem with parameters

We investigate the existence of positive solutions for a nonlinear Riemann–Liouville fractional differential equation with a positive parameter subject to nonlocal boundary conditions, which contain fractional derivatives and Riemann–Stieltjes integrals. The nonlinearity of the equation is nonnegative, and it may have singularities at its variables. In the proof of the main results, we use the fixed point index theory and the principal characteristic value of an associated linear operator. A related semipositone problem is also studied by using the Guo–Krasnosel’skii fixed point theorem