OICC Press International Journal of Mathematical Modelling & Computations 2228-6233 16 3 2026 09 30 A Study on Solving Fractional Volterra Integral Equations with Müntz Orthogonal Functions 224 229 10.57647/ijm2c.2026.1603.18 EN Fereshteh Roustaei Department of Mathematics, Isf. C., Islamic Azad University, Isfahan, Iran Majid Tavassoli Kajani Department of Mathematics, Isf. C., Islamic Azad University, Isfahan, Iran Maryam Bahmanpour Department of Mathematics, Isf. C., Islamic Azad University, Isfahan, Iran https://orcid.org/0000-0002-1379-8096 Journal Article 2026 09 30 In this paper, Müntz orthogonal functions are employed for the numerical solution of fractional Volterra integral equations. These functions are defined on the interval [0, 1] and possess simple and distinct real roots, providing the best unique approximation for functions in L2(0, 1). The Riemann–Liouville fractional integral operator is defined for these functions to reduce computational complexity and increase the solution speed. The error bound of the method is also determined. The numerical examples presented demonstrate the superiority of the proposed method compared to other existing approaches for the numerical solution of fractional Volterra integral equations.