Graef, John R.Tunc, OsmanTunc, Cemil2025-05-102025-05-1020252504-311010.3390/fractalfract90503042-s2.0-105006561400https://doi.org/10.3390/fractalfract9050304The authors consider a nonlinear psi-Hilfer fractional-order Volterra integro-differential equation (psi-Hilfer FrOVIDE) that incorporates N-multiple variable time delays into the equation. By utilizing the psi-Hilfer fractional derivative, they investigate the Ulam-Hyers-Rassias and Ulam-Hyers stability of the equation by using fixed-point methods. Their results improve existing ones both with and without delays by extending them to nonlinear psi-Hilfer FrOVIDEs that incorporate N-multiple variable time delays.eninfo:eu-repo/semantics/openAccessHilfer Fractional-Order Volterra Integro-Differential EquationsUlam-Hyers-Rassias StabilityUlam-Hyers StabilityFixed-Point MethodsArticle95Q1Q1WOS:001496057700001