Uniqueness Results for Positive Solutions of Ψ –Caputo Fractional Differential Equations

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This paper establishes rigorous existence and uniqueness results for positive solutions of boundary value problems involving the Ψ –Caputo fractional operator. The equations combine continuous nonlinear terms with Riemann–Liouville fractional integrals and are subject to newly formulated integral boundary conditions. Using ordered Banach space techniques together with γ ‐concave and subhomogeneous operators, supported by Banach′s fixed point theorem, we derive sharp criteria ensuring a unique positive solution. These findings extend the current theory for fractional boundary value problems governed by mixed integral operators.